THE ANDES OF SOUTHERN 

PERU 



GEOGRAPHICAL RECONNAISSANCE ALONG THE 
SEVENTY-THIRD MERIDIAN 



BY 

ISAIAH BOWMAN 

Director of the American Geographical Society 




PUBLISHED FOR 

THE AMERICAN GEOGRAPHICAL SOCIETY 

OF NEW YORK 

BY 
HENRY HOLT AND COMPANY 

1916 



it^ 



"\1 



COPTUIGHT, 1916 
BT 

HENET HOLT AND COMPANY 




JAN -2 1917 



THE QUmN A BODEN CO. PRESS 
RAHWAY. N. J. 



^V\yO ( 



/ 




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TO 
C. G. B. 



PREFACE 

The geographic work of the Yale Peruvian Expedition of 1911 
was essentially a reconnaissance of the Peruvian Andes along the 
73rd meridian. The route led from the tropical plains of the lower 
Urubamba southward over lofty snow-covered passes to the desert 
coast at Camana. The strong climatic and topographic contrasts 
and the varied human life which the region contains are of geo- 
graphic interest chiefly because they present so many and such 
clear cases of environmental control within short distances. 
Though we speak of "isolated" mountain communities in the 
Andes, it is only in a relative sense. The extreme isolation felt 
in some of the world's great deserts is here unknown. It is there- 
fore all the more remarkable when we come upon differences of 
customs and character in Peru to find them strongly developed in 
spite of the small distances that separate unlike groups of people. 

My division of the Expedition undertook to make a contour map 
of the two-hundred-mile stretch of mountain country between 
Abaneay and the Pacific coast, and a great deal of detailed geo- 
graphic and physiographic work had to be sacrificed to insure the 
completion of the survey. Camp sites, forage, water, and, above 
all, strong beasts for the topographer's difiicult and excessively 
lofty stations brought daily problems that were always serious 
and sometimes critical. I was so deeply interested in the progress 
of the topographic map that whenever it came to a choice of plans 
the map and not the geography was first considered. The effect 
upon my work was to distribute it with little regard to the de- 
mands of the problems, but I cannot regret this in view of the 
great value of the maps. Mr. Kai Hendriksen did splendid work 
in putting through two hundred miles of plane-tabling in two 
months under conditions of extreme difficulty. Many of his tri- 
angulation stations ranged in elevation from 14,000 to nearly 



viii PREFACE 

18,000 feet, and the cold and storms — especially the hailstorms of 
mid-afternoon — were at times most severe. 

It is also a pleasure to say that Mr. Paul Baxter Lanius, my 
assistant on the lower Urubamba journey, rendered an invaluable 
service in securing continuous weather records at Yavero and else- 
where, and in getting food and men to the river party at a critical 
time. Dr. W. G-. Erving, surgeon of the Expedition, accompanied 
me on a canoe journey through the lower gorge of the Urubamba 
between Eosalina and the mouth of the Timpia, and again by pack 
train from Santa Ana to Cotahuasi. For a time he assisted the 
topographer. It is due to his prompt surgical assistance to vari- 
ous members of the party that the field work was uninterrupted. 
He was especially useful when two of our river Indians from 
Pongo de Mainique T^ere accidentally shot. I have since been in- 
formed by their patron that they were at T>rork within a few 
months. 

It is difficult to express the gratitude I feel toward Professor 
Hiram Bingham, Director of the Expedition, first for the execu- 
tive care he displayed in the organization of the expedition's 
plans, which left the various members largely care-free, and sec- 
ond, for generously supplying the time of various assistants in the 
preparation of results. I have enjoyed so many facilities for the 
completion of the work that at least a year's time has been saved 
thereby. Professor Bingham's enthusiasm for pioneer field work 
was in the highest degree stimulating to every member of the 
party. Furthermore, it led to a determination to complete at all 
hazards the original plans. 

Finally, I wish gratefully to acknowledge the expert assistance 
of Miss Gladys M. Wrigley, of the editorial staff of the American 
Geographical Society, who prepared the climatic tables, many of 
the miscellaneous data related thereto, and all of the curves in 
Chapter X. Miss Wrigley also assisted in the revision of Chap- 
ters IX and X and in the correction of the proof. Her eager and 
in the highest degree faithful assistance in these tasks bespeaks 
a true scientific spirit. 

Isaiah Bowman. 



SPECIAL ACKNOWLEDGMENTS FOR ILLUSTRATIONS 

Fig. 28. Pliotograpli by H. L. Tucker, Engineer, Yale Peruvian Expedi- 
tion of 1911. 

Fig. 43. Photograpli by H. L. Tucker. 

Fig. 44. Pbotograph by Professor Hiram Bingliam. 

Figs. 136, 139, 140. Data for' bachured sketcli maps, cbiefly from topo- 
grapbic]_sbeetS'by 'A. H. Bumstead, Topograpber to Professor Bingbam's 
Peruvian Expeditions of 1912 and 1914. 



I 



CONTENTS 

PART I 

HUMAN GEOGRAPHY 

CHAPTBK PAGE 

I. The Regions of Peru I'- 
ll. The Rapids and Canyons of the Urubamba .... 8 

III. The Rubber Forests 22- 

IV. The Forest Indians 36 

V. The Country op the Shepherds 46 

VI. The Border Valleys of the Eastern Andes . . . . 68 
VII. The Geographic Basis of Revolutions and of Human 

Character in the Peruvian Andes 88 

VIII. The Coastal Desert 110 

IX. Climatology of the Peruvian Andes 12L 

X. Meteorological Records from the Peruvla.n Andes . . 157 - 

PART II 

PHYSIOGRAPHY OF THE PERUVIAN ANDES 

XI. The Peruvian Landscape 183 

XII. The Western Andes: The Maritime Cordillera or Cor- 
dillera Occidental 199 

XIII. The Eastern Andes : The Cordillera Vilcapampa . . 204 

XIV. The Coastal Terraces 225 

XV. Physiographic and Geologic Development .... 233 

XVI. Glacial Features ' . . 274 

Appendix A. Survey Methods Employed in the Construction of 

the Seven Accompanying Topographic Sheets . 315 

Appendix B. Fossil Determinations 321 

Appendix C. Key to Place Names 324 

Index 327 

TOPOGRAPHIC SHEETS 

Camana Quadrangle 114 

Aplao " 120 

Coropuna " 188 

Cotahuasi " 192 

La Cumbre " 202 

Antabamba " 282 

Lambrama " 304 



PART I 
HUMAN GEOGRAPHY 

CHAPTER I 

THE REGIONS OF PERU 

Let four Peruvians begin this book by telling what manner of 
country they live in. Their ideas are provincial and they have a 
fondness for exaggerated description: but, for all that, they will 
reveal much that is true because they will at least reveal them- 
selves. Their opinions reflect both the spirit of the toiler on the 
land and the outlook of the merchant in the town in relation to 
geography and national problems. Their names do not matter; 
let them stand for the four human regions of Peru, for they are 
in many respects typical men. 

The Forest Dweu:.ee 

One of them I met at a rubber station on the lower Urubamba 
Eiver.^ He helped secure my canoe, escorted me hospitably to his 
hut, set food and drink before me, and talked of the tropical forest, 
the rubber business, the Indians, the rivers, and the trails. In his 
opinion Peru was a land of great forest resources. Moreover, 
the fertile plains along the river margins might become the sites 
of rich plantations. The rivers had many fish and his garden 
needed only a little cultivation to produce an abundance of food. 
Fruit trees grew on every hand. He had recently married the 
daughter of an Indian chief. 

Formerly he had been a missionary at a rubber station on the 
Madre de Dios, where the life was hard and narrow, and he doubted 
if there were any real converts. Himself the son of an English- 
man and a Chilean woman, he found, so he said, that a mission- 
ary's life in the rubber forest was intolerable for more than a few 

^ For all locations mentioned see maps accompanying thei text or Appendix C. 



2 THE ANDES OF SOUTHERN PERU 

years. Yet he had no fault to find with the religious system of 
which he had once formed a part; in fact he had still a certain 
curious mixed loyalty to it. Before I left he gave me a photo- 
graph of himself and said with little pride and more sadness that 
perhaps I would remember him as a man that had done some good 
in the world along with much that might have been better. 

We shall understand our interpreter better if we know who 
his associates were. He lived with a Frenchman who had spent 
several years in Africa as a soldier in the "Foreign Legion." If 
you do not know what that means, you have yet all the pleasure 
of an interesting discovery. The Frenchman had reached the sta- 
tion the year before quite destitute and clad only in a shirt and 
a pair of trousers. A day's journey north lived a young half- 
breed — son of a drunken father and a Machiganga woman, who 
cheated me so badly when I engaged Indian paddlers that I should 
almost have preferred that he had robbed me. Yet in a sense he 
had my life in his hands and I submitted. A German and a native 
Peruvian ran a rubber station on a tributary two days' journey 
from the first. It will be observed that the company was mixed. 
They were all Peruvians, but of a sort not found in such relative 
abundance elsewhere. The defeated and the outcast, as well as 
the pioneer, go doAvn eventually to the hot forested lands where 
men are forgotten. 

While he saw gold in every square mile of his forested region, 
my clerical friend saw misery also. The brutal treatment of the 
Indians by the whites of the Madre de Dios country he could speak 
of only as a man reviving a painful memory. The Indians at the 
station loved him devotedly. There was only justice and kind- 
ness in aU his dealings. Because he had large interests to look 
after, he knew all the members of the tribe, and his word was law 
in no hackneyed sense. A kindlier man never lived in the rubber 
forest. His influence as a high-souled man of business was vastly 
greater than as a missionary in this frontier society. He could 
daily illustrate by practical example what he had formerly been 
able only to preach. 

He thought the life of the Peruvian cities debasing. The 




Fig. 1. 




Fig. 2. 



Fig. 1 — Tropical vegetation, clearing on the river bank and rubber station at 
Pongo de Mainique. The pronounced scarp on the northeastern border of the Andes 
is seen in the right background. 

Fig. 2 — Pushing a heavy dugout against the current in the rapids below Pongo de 
Mainique. The Indian boy and his father in the canoe had been accidentally shot. 




Fig. 3 — From ice to sugar cane, Urubaniba Valley, at Colpani. On tlie north- 
eastern border of the Cordillera Vilcapampa looking upstream. In the extreme back- 
ground and thirteen sixteenths of an inch from the top of the picture is the sharp 
peak of Salcantay. Only the lower end of the more open portion of the Canyon of 
Xorontoy is here shown. There is a field of sugar cane in the foreground and the 
valley trail is shown on the opposite side of the river. 



t^ 



THE REGIONS OF BERU 3 

coastal valleys were small and dry and the men who lived there 
were crowded and poor (sic). The plateau was inhabited by In- 
dians little better than brutes. Surely I could not think that the 
fine forest Indian was lower than the so-called civilized Indian of 
the plateau. There was plenty of room in the forest; and there 
was wealth if you knew how to get at it. Above all you were far 
from the annoying officials of the government, and therefore could 
do much as you pleased so long as you paid your duties on rubber 
and did not wantonly kill too many Indians. 

For all his kindly tolerance of men and conditions he yet found 
fault with the government. "They" neglected to build roads, to 
encourage colonization, and to lower taxes on the forest products, 
which were always won at great risk. Nature had done her part 
well — it was only government that hindered. Moreover, the for- 
ested region was the land of the future. If Peru was to be a great 
nation her people would have to live largely upon the eastern 
plains. Though others spoke of "going in" and "coming out" of 
the rubber country as one might speak of entering and leaving a 
dungeon, he always spoke of it as home. Though he now lived 
in the wilderness he hoped to see the day when plantations cov- 
ered the plains. A greater Peru and the forest were inseparable 
ideas to him. 

The Eastern Valley Planter 

My second friend lived in one of the beautiful mountain val- 
leys of the eastern Andes. We walked through his clean cacao 
orchards and cane fields. Like the man in the forest, he believed 
in the thorough inefficiency of the government; otherwise why 
were there no railways for the cheaper transportation of the val- 
ley products, no dams for the generation of power and the storage 
of irrigation water, not even roads for mule carts 1 Had the gov- 
ernment been stable and efficient there would now be a dense popu- 
lation in the eastern valleys. Eevolutions were the curse of these 
remote sections of the country. The ne'er-do-wells became gen- 
erals. The loafer you dismissed today might demand ten thou- 
sand dollars tomorrow or threaten to destroy your plantation. 



4 THE ANDES OF SOUTHERN PERU 

The govermneiit troops might come to help you, but they were 
always too late. 

For this one paid most burdensome taxes. Lima profited 
thereby, not the valley planters. The coast people were the 
favored of Peru anyhow. They had railroads, good steamer 
service, public improvements at government expense, and com- 
paratively light taxes. If the government were impartial the 
eastern valleys also would have railways and a dense population. 
Who could tell? Perhaps the capital city might be here. Cer- 
tainly it was better to have Lima here than on the coast where 
the Chileans might at any time take it again. The blessings of 
the valleys were both rich and manifold. Here was neither a cold 
plateau nor the hot plains, but fertile valleys with a vernal climate. 

We talked of much else, but our conversation had always the 
pioneer flavor. And though an old man he saw always the future 
Peru gromng wonderfully rich and powerful as men came to rec- 
ognize and use the resources of the eastern valleys. This too was 
the optimism of the pioneer. Once started on that subject he grew 
eloquent. He was provincial but he was also intensely patriotic. 
He never missed an opportunity to impress upon his guests that 
a great state would arise when people and rulers at last recog- 
nized the wealth of eastern Peru. 

The Highland Shepherd 

The people who live in the lofty highlands and mountains of 
Peru have several months of real winter weather despite their 
tropical latitude. In the midst of a snowstorm in the Maritime 
Cordillera I met a solitary traveler bound for Cotahuasi on the 
floor of a deep canyon a day's journey toward the east. It was 
noon and we halted our pack trains in the lee of a huge rock shelter 
to escape the bitter wind that blew dowm from the snow-clad peaks 
of Solimana. Men who follow the same trails are fraternal. In 
a moment we had food from our saddle-bags spread on the snow 
under the corner of a poncho and had exchanged the best in each 
other's collection as naturally as friends exchange greetings. By 
the time I had told him whence and why in response to his inevita- 



THE REGIONS OF PERU 5 

ble questions we had finished the food and had gathered a heap 
of tola bushes for a fire. The arriero (muleteer) brought water 
from a spring in the hollow below us. Though the snow thick- 
ened, the wind fell. We were comfortable, even at 16,000 feet, 
and called the place "The Salamanca Club." Then I questioned 
him, and this is what he said : 

"I live in the deep valley of Cotahuasi, but my lands lie chiefly 
up here on the plateau. My f amUy has held title to this puna ever 
since the Wars of Liberation, except for a few years after one of 
our "early revolutions. I travel about a great deal looking after 
my flocks. Only Indians live up here. Away off yonder beyond 
that dark gorge is a group of their huts, and on the bright days 
of summer you may see their sheep, llamas, and alpacas up here, 
for on the floors of the watered valleys that girdle these volcanoes 
there are more tender grasses than grow on this despoblado. I 
give them corn and barley from my irrigated fields in the valley ; 
they give me wool and meat. The alpaca wool is most valuable. 
It is hard to get, for the alpaca requires short grasses and plenty 
of water, and you see there is only coarse tufted ichu grass about 
us, and there are no streams. It is all right for llamas, but alpacas 
require better forage. 

"No one can imagine the poverty and ignorance of these moun- 
tain shepherds. They are filthier than beasts. I have to watch 
them constantly or they would sell parts of the flocks, which 
do not belong to them, or try to exchange the valuable alpaca wool 
for coca leaves in distant towns. They are frequently drunk." 

"But where do they get the drink? " I asked. "And what do 
you pay them? " 

' ' Oh, the drink is chiefly imported alcohol, and also chicha made 
from corn. They insist on having it, and do better when I bring 
them a little now and then. They get much more from the deal- 
ers in the towns. As for pay, I do not pay them anything in 
money except when they bring meat to the valley. Then I give 
them a few reales apiece for the sheep and a little more for the 
llamas. The flocks all belong to me really, but of course the poor 
Indian must have a little money. Besides, I let him have a part 



6 THE ANDES OF SOUTHERN PERU 

of the yearly increase. It is not much, but he has always lived 
this way and I suppose that he is contented after a fashion." 

Then he became eager to tell what wealth the mountains con- 
tained in soil and climate if only the right grasses were intro- 
duced by the government. 

"Here, before us, are vast punas almost without habitations. 
If the officials would bring in hardy Siberian grasses these lava- 
covered plateaus might be carpeted with pasture. There would be 
villages here and there. The native Indians easily stand the alti- 
tude. This whole Cordillera might have ten times as many people. 
Why does the government bother about concessions in the rubber 
forests and roads to the eastern valleys when there are these vast 
tracts only requiring new seeds to develop into rich pastures? 
The government could thus greatly increase its revenues because 
there is a heavy tax on exported wool." 

Thus he talked about the bleak Cordillera until we forgot the 
pounding of our hearts and our frequent gasps for breath on ac- 
count of the altitude. His rosy picture of a well-populated high- 
land seemed to bring us down nearer sea level where normal folks 
lived. To the Indians the altitude is nothing. It has an effect, but 
it is slight; at any rate they manage to reproduce their kind at 
elevations that would kill a white mother. If alcohol were abol- 
ished and better grasses introduced, these lofty pastures might 
indeed support a much larger population. The sheep pastures of 
the world are rapidly disappearing before the march of the farmer. 
Here, well above the limit of cultivation, is a permanent range, 
one of the great as well as permanent assets of Peru. 

The Coastal Plantee 

The man from the deep Majes Valley in the coastal desert rode 
out with me through cotton fields as rich and clean as those of a 
Texas plantation. He was tall, straight-limbed, and clear-eyed — 
one of the energetic younger generation, yet with the blood of a 
proud old family. We forded the river and rode on through vine- 
yards and fig orchards loaded with fruit. His manner became 
deeply earnest as he pictured the future of Peru, when her people 




Fig. 4. 




Fig. 5. 



Fig. 4 — Large ground moss — so-called yareta — used for fuel. It occurs in the zone 
of Alpine vegetation and is best developed in regions where the snowline is highest. 
The photograph represents a t3'pical occurrence between Cotahuasi and Salamanca, 
elevation 16,000 feet (4,880 m.). The snowline is here at 17,500 feet (5,333 m.). In 
the foreground is the most widely distributed toJa bush, also used for fuel. 

Fig. 5 — Expedition's camp near Lambrama, 15,500 feet (4,720 m. ), after a snow- 
storm. The location is midway in the pasture zone. 




Fig. 6. 





.-ik,^. 



^^\. 



Fig. 7. 



Fig. 6 — Irrigated Chili Valley on the outskirts of Arequipa. The lower slopes 
of El Misti are in the left background. The Alto de los Hucsos or Plateau of Bones 
lies on the farther side of the valley. 

Fig. 7 — Crossing the highest pass (Chiiquito) in tlie Cordillera Vilcapanipa, 14,500 
feet {4,420 m.). Grazing is here carried on up to the snowline. 



THE REGIONS OF PERU 7 

would take advantage of scientific methods and use labor-saving 
machinery. He said that the methods now in use were medieval, 
and he pointed to a score of concrete illustrations. Also, here was 
water running to waste, yet the desert was on either hand. There 
should be dams and canals. Every drop of water was needed. 
The population of the valley could be easily doubled. 

Capital was lacking but there was also lacking energy among 
the people. Slipshod methods brought them a bare living and 
they were too easily contented. Their standards of life should be 
elevated. Education was still for the few, and it should be uni- 
versal. A new spirit of progress was slowly developing — a more 
general interest in public affairs, a desire to advance with the 
more progressive nations of South America, — and when it had 
reached its culmination there would be no happier land than 
coastal Peru, already the seat of the densest populations and the 
most highly cultivated fields. 

These four men have portrayed the four great regions of Peru 
— the lowland plains, the eastern mountain valleys, the lofty 
plateaus, and the valley oases of the coast. This is not all of 
Peru. The mountain basins have their own peculiar qualities and 
the valley heads of the coastal zone are unlike the lower valleys 
and the plateau on either hand. Yet the chief characteristics of 
the country are set forth with reasonable fidelity in these indi- 
vidual accounts. Moreover the spirit of the Peruvians is better 
shown thereby than their material resources. If this is not Peru, 
it is what the Peruvians think is Peru, and to a high degree a 
man's country is what he thinks it is — at least it is little more to 
him. 



CHAPTER II 
THE RAPIDS AND CANYONS OF THE URUBAMBA 

Among the scientifically unexplored regions of Peru there is 
no other so alluring to the geographer as the vast forested realm 
on the eastern border of the Andes. Thus it happened that within 
two weeks of our arrival at Cuzco we followed the northern trail 
to the great canyon of the Urubamba (Fig. 8), the gateway to the 
eastern valleys and the lowland plains of the Amazon. It is here 
that the adventurous river, reenforced by hundreds of mountain- 
born tributaries, finally cuts its defiant way through the last of its 
great topographic barriers. More than seventy rapids interrupt 
its course; one of them, at the mouth of the Sirialo, is at least a 
half-mile in length, and long before one reaches its head he hears 
its roaring from beyond the forest-clad mountain spurs. 

The great bend of the Urubamba in which the line of rapids 
occurs is one of the most curious hydrographic features in Peru. 
The river suddenly changes its general northward course and 
striking south of west flows nearly fifty miles toward the axis of 
the mountains, where, turning almost in a complete circle, it makes 
a final assault upon the eastern mountain ranges. Fifty miles 
farther on it breaks through the long sharp-crested chain of the 
Front Range of the Andes in a splendid gorge more than a half- 
mile deep, the famous Pongo de Mainique (Fig. 9). 

Our chief object in descending the line of rapids was to study 
the canyon of the Urubamba below Rosalina and to make a topo- 
graphic sketch map of it. We also mahed to know what secrets 
might be gathered in this hitherto unexplored stretch of country, 
what people dwelt along its banks, and if the vague tales of de- 
serted towns and fugitive tribes had any basis in fact. 

We could gather almost no information as to the nature of the 
river except from the report of Major Kerbey, an American, who, 
in 1897, descended the last twenty miles of the one hundred we 
proposed to navigate. He pronounced the journey more hazard- 



THE RAPIDS AND CANYONS OF THE URUBAMBA 




Fig. 8 — Sketch map showing the route of the Yale- Peruvian Expedition of 1911 
down the Urubamba Valley, together with the area of the main map and the changes 
in the delineation of the bend of the Urubamba resulting from the surveys of the 
Expedition. Based on the " Mapa que comprende las ultimas exploraciones y estudios 
verificados desde 1900 hasta 1906," 1:1,000,000, Bol. Soe. Geogr. Lima, Vol. 25, No. 3, 
1909. For details of the trail from Eosalina to Pongo de Mainique see " Piano de las 
Secciones y Afluentes del Rio Urubamba: 1902-1904, scale 1:150,000 by Luis M. 
Robledo in Bol. Soc. Gteogr. Lima, Vol. 25, No. 4, 1909. Only the lower slopes of 
the long mountain spurs can be seen from the river; hence only in a few places could 
observations be made on the topography of distant ranges. Paced distances of a half 
mile at irregular intervals were used for the estimation of longer distances. Direc- 
tions were taken by compass corrected for magnetic deviation as determined on the 
seventy -third meridian (See Appendix A). The position of Rosalina on Robledo's 
map was taken as a base. 



10 THE ANDES OF SOUTHERN PERU 

ous than Major Powell's famous descent of the Grand Canyon in 
1867 — an obvious exaggeration. He lost his canoe in a treacher- 
ous rapid, was deserted by his Indian guides, and only after a 
painful march through an all but impassable jungle was he finally 
able to escape on an abandoned raft. Less than a dozen have 
ventured down since Major Kerbey's day. A Peruvian mining 
engineer descended the river a few years ago, and four Italian 
traders a year later floated down in rafts and canoes, losing al- 
most all of their cargo. For nearly two months they were 
marooned upon a sand-bar waiting for the river to subside. At 
last they succeeded in reaching Mulanquiato, an Indian settlement 
and plantation owned by Pereira, near the entrance to the last 
canyon. Their attempted passage of the worst stretch of rapids 
resulted in the loss of all their rubber cargo, the work of a year. 
Among the half dozen others who have made the journey — Indians 
and slave traders from down-river rubber posts — there is no rec- 
ord of a single descent without the loss of at least one canoe. 

To reach the head of canoe navigation we made a two weeks' 
muleback journey north of Cuzco through the steep-walled granite 
Canyon of Torontoy, and to the sugar and cacao plantations of the 
middle Urubamba, or Santa Ana Valley, where we outfitted. At 
Echarati, thirty miles farther on, where the heat becomes more in- 
tense and the first patches of real tropical forest begin, we were 
obliged to exchange our beasts for ten fresh animals accustomed to 
forest work and its privations. Three days later we pitched our 
tent on the river bank at Eosalina, the last outpost of the valley set- 
tlements. As we dropped down the steep mountain slope before 
striking the river flood plain, we passed two half-naked Machi- 
ganga Indians perched on the limbs of a tree beside the trail, our 
first sight of members of a tribe whose territory we had now en- 
tered. Later in the day they crossed the river in a dugout, landed 
on the sand-bar above us, and gathered brush for the nightly fire, 
around which they lie wrapped in a single shirt woven from the 
fiber of the wild cotton. 

Eosalina is hardly more than a name on the map and a camp 
site on the river bank. Some distance back from the left bank of 




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1^ -Mawr^v-",; v»-,j'ii ■!- 



Fig. 11. 




FiQ. 12. 



Fig. 11 — A temporary shelter-hut on a sand-bar near tlie great bend of the Uru- 
bamba (see map, Fig. 8). The Machiganga Indians use these cane shelters during the 
fishing season, when the river is low. 

Fig. 12 — Thirty-foot canoe in a rapid above Pongo de Mainicjue. 



THE RAPIDS AND CANYONS OF THE URUBAMBA 11 

the river is a sugar plantation, whose owner lives in the cooler 
mountains, a day's journey away; on the right bank is a small 
clearing planted to sugar cane and yuca, and on the edge of it is 
a reed hut sheltering three inhabitants, the total population of 
Eosalina. The owner asked our destination, and to our reply that 
we should start in a few days for Pongo de Mainique he offered 
two serious objections. No one thought of arranging so difficult 
a journey in less than a month, for canoe and Indians were diffi- 
cult to find, and the river trip was dangerous. Clearly, to start 
without the loss of precious time would require unusual exertion. 
We immediately despatched an Indian messenger to the owner 
of the small hacienda across the river whUe one of our peons car- 
ried a second note to a priest of great influence among the forest 
Indians, Padre Mendoza, then at his other home in the distant 
mountains. 

The answer of Senor Morales was his appearance in person to 
offer the hospitality of his home and to assist us in securing canoe 
and oarsmen. To our note the Padre, from his hill-top, sent a 
polite answer and the offer of his large canoe if we would but 
guarantee its return. His temporary illness prevented a visit 
to which we had looked forward with great interest. 

The morning after our arrival I started out on foot in 
company with our arriero in search of the Machigangas, who 
fish and hunt along the river bank during the dry season and re- 
tire to their hill camps when the heavy rains begin. "We soon left 
the well-beaten trail and, following a faint woodland path, came 
to the river bank about a half day's journey below Eosalina. 
There we found a canoe hidden in an overhanging arch of vines, 
and crossing the river met an Indian family who gave us further 
directions. Their vague signs were but dimly understood and we 
soon found ourselves in the midst of a carrizo (reed) swamp 
filled with tall bamboo and cane and crossed by a network of inter- 
lacing streams. We followed a faint path only to find ourselves 
climbing the adjacent mountain slopes away from our destination. 
Once again in the swamp we had literally to cut our way through 
the thick cane, wade the numberless brooks, and follow wild ani- 



12 THE ANDES OF SOUTHERN PERU 

mal trails until, late in the day, famished and thirsty, we came 
upon a little clearing on a sand-bar, the hut of La Sama, who 
knew the Machigangas and their villages. 

After our long day's work we had fish and yuca, and water 
to which had been added a little raw cane sugar. Late at night 
La Sama returned from a trip to the Lidian villages down river. 
He brought with him a half-dozen Machiganga Indians, boys and 
men, and around the camp fire that night gave us a dramatic ac- 
count of his former trip down river. At one point he leaped to 
his feet, and with an imaginary pole shifted the canoe 'in a SAvift 
rapid, turned it aside from imminent wreck, and shouting at the 
top of his voice over the roar of the water finally succeeded in 
evading what he had made seem certain death in a whirlpool. We 
kept a fire going all night long for we slept upon the ground with- 
out a covering, and, strange as it may appear, the cold seemed in- 
tense, though the minimum thermometer registered 59° F. The 
next morning the whole party of ten sunned themselves for nearly 
an hour until the flies and heat once more drove them to shelter. 

Returning to camp next day by a different route was an experi- 
ence of great interest, because of the light it threw on hidden trails 
known only to the Indian and his friends. Slave raiders in former 
years devastated the native villages and forced the Indian to con- 
ceal his special trails of refuge. At one point we traversed a 
cliff seventy-five feet above the river, walking on a narrow ledge 
no wider than a man's foot. At another point the dim trail ap- 
parently disappeared, but when we had climbed hand over hand 
up the face of the cliff, by hanging vines and tree roots, we came 
upon it again. Crossing the river in the canoe we had used the 
day before, we shortened the return by wading the swift Chi- 
rumbia waist-deep, and by crawling along a cliff face for nearly an 
eighth of a mile. At the steepest point the river had so under- 
cut the face that there was no trail at all, and we s^\^lng fully fif- 
teen feet from one ledge to another, on a hanging vine high above 
the river. 

After two days' delay we left Eosalina late in the afternoon 
of August 7. My party included several Machiganga Indians, La 



THE RAPIDS AND CANYONS OF THE URUBAMBA 13 

Sama, and Dr. W. G. Erving, surgeon of the expedition. Mr. P. 
B. Lanius, Moscoso (the arriero), and two peons were to take the 
pack train as far as possible toward the rubber station at Pongo 
de Mainique where preparations were to be made for our arrival. 
At the first rapid we learned the method of our Indian boatmen. 
It was to run the heavy boat head on into shallow water at one 
side of a rapid and in this way "brake" it down stream. Heavily 
loaded with six men, 200 pounds of baggage, a dog, and supplies 
of yuca and sugar cane our twenty-five foot dugout canoe was as 
rigid as a steamer, and we dropped safely down rapid after rapid 
until long after dark, and by the light of a glorious tropical moon 
we beached our craft in front of La Sama's hut at the edge of 
the cane swamp. 

Here for five days we endured a most exasperating delay. La 
Sama had promised Indian boatmen and now said none had yet 
been secured. Each day Indians were about to arrive, but by 
nightfall the promise was broken only to be repeated the follow- 
ing morning. To save our food supply — we had taken but six 
days' provisions — we ate yuca soup and fish and some parched 
corn, adding to this only a little from our limited stores. At last 
we could wait no longer, even if the map had to be sacrificed to 
the work of navigating the canoe. Our determination to leave 
stirred La Sama to final action. He secured an assistant named 
Wilson and embarked with us, planning to get Indians farther 
down river or make the journey himself. 

On August 12, at 4.30 P. M., we entered upon the second stage 
of the journey. As we shot down the first long rapid and rounded 
a wooded bend the view down river opened up and gave us our 
first clear notion of the region we had set out to explore. From 
mountain summits in the clouds long trailing spurs descend to the 
river bank. In general the slopes are smooth-contoured and for- 
est-clad from summit to base; only in a few places do high cliffs 
diversify the scenery. The river vista everywhere includes a 
rapid and small patches of playa or flood plain on the inside of 
the river curves. Although a true canyon hems in the river at 
two celebrated passes farther doAvn, the upper part of the river 



14 THE ANDES OF SOUTHERN PERU 

flows in a somewhat open valley of moderate relief, with here and 
there a sentinel-like peak next the river. 

A light shower fell at sunset, a typical late-afternoon down- 
pour so characteristic of the tropics. We landed at a small en- 
campment of Machigangas, built a fire against the scarred trunk 
of a big palm, and made up our beds in the open, covering them 
with our rubber ponchos. Our Indian neighbors gave us yuca and 
corn, but their neighborliness went no further, for when our boat- 
men attempted to sleep under their roofs' they drove them out and 
fastened as securely as possible the shaky door of their hut. 

All our efforts to obtain Indians, both here and elsewhere, 
proved fruitless. One excuse after another was overcome; they 
plainly coveted the trinkets, knives, machetes, muskets, and am- 
munition that we offered them; and they appeared to be friendly 
enough. Only after repeated assurances of our friendship could 
we learn the real reason for their refusal. Some of them were 
escaped rubber pickers that had been captured by white raiders 
several years before, and for them a return to the rubber country 
meant enslavement, heavy floggings, and separation from their 
numerous wives. The hardships they had endured, their final 
escape, the cruelty of the rubber men, and the difficult passage of 
the rapids below were a set of circumstances that nothing in our 
list of gifts could overcome. My first request a week before had so 
sharpened their memory that one of them related the story of his 
wrongs, a recital intensely dramatic to the whole circle of his 
listeners, including myself. Though I did not understand the de- 
tails of his story, his tones and gesticulations were so effective 
that they held me as well as his kinsmen of the woods spellbound 
for over an hour. 

It is appalling to what extent this great region has been de- 
populated by the slave raiders and those arch enemies of the 
savage, smallpox and malaria. At Eosalina, over sixty Indians 
died of malaria in one year ; and only twenty years ago seventy of 
them, the entire population of the Pongo, were swept away by 
smallpox. For a week we passed former camps near small aban- 
doned clearings, once the home of little groups of Machigangas. 



THE RAPIDS AND CANYONS OF THE URUBAMBA 15 

Even tlie summer shelter Imts on the sand-bars, where the Indians 
formerly gathered from their hill homes to fish, are now almost 
entirely abandoned. Though our men carefully reconnoitered each 
one for fear of ambush, the precaution was needless. Below the 
Coribeni the Urubamba is a great silent valley. It is fitted by 
Nature to support numerous villages, but its vast solitudes are 
unbroken except at night, when a few families that live in the hills 
slip down to the river to gather yuca and cane. 

By noon of the second day's journey we reached the head of 
the great rapid at the mouth of the Sirialo. We had already run 
the long Coribeni rapid, visited the Indian huts at the junction 
of the big Coribeni tributary, exchanged our canoe for a larger 
and steadier one, and were now to run one of the ugliest rapids of 
the upper river. The rapid is formed by the gravel masses that 
the Sirialo brings down from the distant Cordillera Vilcapampa. 
They trail along for at least a half-mile, split the river into two 
main currents and nearly choke the mouth of the tributary. For 
almost a mile above this great barrier the main river is ponded 
and almost as quiet as a lake. 

We let our craft down this rapid by ropes, and in the last dif- 
ficult passage were so roughly handled by our almost unmanagea- 
ble canoe as to suffer from several bad accidents. All of the party 
were injured in one way or another, while I suffered a fracture 
sprain of the left foot that made painful work of the rest of the 
river trip. 

At two points below Eosalina the Urubamba is shut in by steep 
mountain slopes and vertical cliffs. Canoe navigation below the 
Sirialo and Coribeni rapids is no more hazardous than on the 
rapids of our northern rivers, except at the two "pongos" or nar- 
row passages. The first occurs at the sharpest point of the abrupt 
curve shown on the map; the second is the celebrated Pongo de 
Mainique. In these narrow passages in time of high water there 
is no landing for long stretches. The bow paddler stands well 
forward and tries for depth and current; the stern paddler keeps 
the canoe steady in its course. When paddlers are in agreement 
even a heavy canoe can be directed into the most favorable chan- 



16 THE ANDES OF SOUTHERN PERU 

nels. Oui" canoemen were always in disagreement, however, and 
as often as not we shot down rapids at a speed of twenty miles an 
hour, broadside on, with an occasional bump on projecting rocks 
or boulders whose warning ordinary boatmen would not let go 
unheeded. 

The scenery at the great bend is unusually beautiful. The 
tropical forest crowds the river bank, great cliffs rise sheer from 
the water's edge, their faces overhung with a trailing drapery of 
vines, and in the longer river vistas one may sometimes see the 
distant heights of the Cordillera Vilcapampa. We shot the long 
succession of rapids in the first canyon without mishap, and at 
night pitched our tent on the edge of the river near the mouth of 
the Manugali. 

From the sharp peak opposite our camjD we saw for the first 
time the phenomenon of cloud-banners. A light breeze was blow- 
ing from the western mountains and its vapor was condensed into 
clouds that floated down the wind and dissolved, while they were 
constantly forming afresh at the summit. In the night a thunder- 
storm arose and swept with a roar through the vast forest above 
us. The solid canopy of the tropical forest fairly resounded with 
the impact of the heavy raindrops. The next morning all the 
brooks from the farther side of the river were in flood and the 
river discolored. When we broke camp the last mist wraiths of 
the storm were still trailing through the tree-tops and wrapped 
about the peak opposite our camp, only parting now and then to 
give us delightful glimpses of a forest-clad summit riding high 
above the clouds. 

The alternation of deeps and shallows at this point in the river 
and the well-developed canyon meanders are among the most cele- 
brated of their kind in the world. Though shut in by high cliffs 
and bordered by mountains the river exhibits a succession of 
curves so regular that one might almost imagine the country a 
plain from the pattern of the meanders. The succession of smooth 
curves for a long distance across existing mountains points to a 
time when a lowland plain with moderate slopes drained by 
strongly meandering rivers was developed here. Uplift afforded 



THE RAPIDS AND CANYONS OF THE URUBAMBA IT 

a chance for renewed down-cutting on the part of all the 
streams, and the incision of the meanders. The present meanders 
are, of course, not the identical ones that were formed on the low- 
land plain; they are rather their descendants. Though they stUl 
retain their strongly curved quality, and in places have almost 
cut through the narrow spurs between meander loops, they are not 
smooth like the meanders of the Mississippi. Here and there are 
sharp irregular turns that mar the symmetry of the larger curves. 
The alternating bands of hard and soft rock have had a large part 
in making the course more irregular. The meanders have re- 
sponded to the rock structure. Though regular in their broader 
features they are irregular and deformed in detail. 

Deeps and shallows are known in every vigorous river, but it is 
seldom that they are so prominently developed as in these great 
canyons. At one point in the upper canyon the river has been 
broadened into a lake two or three times the average width of the 
channel and with a scarcely perceptible current ; above and below 
the "laguna," as the boatmen call it, are big rapids with beds so 
shallow that rocks project in many places. In the Pongo de 
Mainique the river is at one place only fifty feet wide, yet so deep 
that there is little current. It is on the banks of the quiet 
stretches that the red forest deer grazes under leafy arcades. 
Here, too, are the boa-constrictor trails several feet wide and bare 
like a roadway. At night the great serpents come trailing down 
to the river's edge, where the red deer and the wildcat, or so- 
called "tiger," are their easy prey. 

It is in such quiet stretches that one also finds the vast colonies 
of water skippers. They dance continuously in the sun with an in- 
cessant motion from right to left and back again. Occasionally 
one dances about in circles, then suddenly darts through the entire 
mass, though without striking his equally erratic neighbors. An 
up-and-down motion still further complicates the effect. It is posi- 
tively bewildering to look intently at the whirling multitude and 
try to follow their complicated motions. Every slight breath of 
wind brings a shock to the organization of the dance. For though 
they dance only in the sun, their favorite places are the sunny 



18 THE ANDES OF SOUTHERN PERU 

spots in the shade near the bank, as beneath an overhanging tree. 
When the wind shakes the foliage the mottled pattern of shade and 
sunlight is confused, the dance slows down, and the dancers be- 
come bewildered. In a storm they seek shelter in the jungle. The 
hot, quiet, sunlit days bring out literally millions of these tiny 
creatures. 

One of the longest deeps in the whole Urubamba lies just above 
the Pongo at Mulanquiato. We drifted down with a gentle cur- 
rent just after sunset. Shrill whistles, like those of a steam 
launch, sounded from either bank, the strange piex'cing notes of 
the lowland cicada, cicada tibicen. Long decorated canoes, bet- 
ter than any we had yet seen, were drawn up in the quiet coves. 
Soon we came upon the first settlement. The owner, Seuor 
Pereira, has gathered about him a group of Machigangas, and by 
marrying into the tribe has attained a position of great influence 
among the Indians. Upon our arrival a gun was fired to announce 
to his people that strangers had come, upon which the Machi- 
gangas strolled along in twos and threes from their huts, helped 
us ashore with the baggage, and prepared the evening meal. Here 
we sat down with five Italians, who had ventured into the rabber 
fields with golden ideas as to profits. After having lost the larger 
part of their merchandise, chiefly cinchona, in the rapids the year 
before, they had established themselves here with the idea of pick- 
ing rubber. Without capital, they followed the Avays of the itiner- 
ant rubber picker and had gathered "caucho," the poorer of the 
two kinds of rubber. No capital is required; the picker simply 
cuts down the likeliest trees, gathers the coagulated sap, and floats 
it down-stream to market. After a year of this life they had 
grown restless and were venturing on other schemes for the great 
down-river rubber country. 

A few weeks later, on returning through the forest, we met 
their carriers with a few small bundles, the only part of their 
cargo they had saved from the river. Without a canoe or the 
means to buy one they had built rafts, which were quickly torn to 
pieces in the rapids. We, too, should have said "pobres Italianos" 
if their venture had not been plainly foolish. The rubber terri- 



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Fig. 15. 




&.;^££A 



Fig. 15 — Topography and vegetation from the Tocate pass, 7,100 feet (2,164 m.), 
between Rosalina and Pongo de Mainique. See Fig. 53a. This is in the zone of 
maximum rainfall. The cumulo-nimbus clouds are typical and change to nimbus in 
the early afternoon. 

Fig. 16 — The Expedition's thirty-foot canoe at the mouth of the Timpia below 
Pongo de Mainique. 



THE RAPIDS AND CANYONS OF THE URUBAMBA 19 

tory is difficult enougli for men with capital; for men with- 
out capital it is impossible. Such men either become affiliated 
with organized companies or get out of the region when they 
can. A few, made desperate by risks and losses, cheat and steal 
their way to rubber. Two years before our trip an Italian had 
murdered two Frenchmen just below the Pongo and stolen their 
rubber cargo, whereupon he was shot by Machigangas under the 
leadership of Domingo, the chief who was with us on a journey 
from Pongo de Mainique to the mouth of the Timpia. After- 
ward they brought his skull to the top of a pass along the forest 
trail and set it up on a cliff at the very edge of Machiganga-land 
as a warning to others of his kind. 

At Mulanquiato we secured five Machigangas and a boy inter- 
preter, and on August 17 made the last and most difficult portion 
of our journey. We found these Indians much more skilful than 
our earlier boatmen. Well-trained, alert, powerful, and with ex- 
cellent team-play, they swept the canoe into this or that thread 
of the current, and took one after another of the rapids with the 
greatest confidence. No sooner had we passed the Sintulini rapids, 
fuUy a mile long, than we reached the mouth of the Pomareni. 
This swift tributary comes in almost at right angles to the main 
river and gives rise to a confusing mass of standing waves and 
conflicting currents rendered still more difficult by the whirlpool 
just below the junction. So swift is the circling current of the 
maelstrom that the water is hollowed out like a great bowl, a really 
formidable point and one of our most dangerous passages ; a little 
too far to the right and we should be thrown over against the cliff- 
face; a little too far to the left and we should be caught in the 
whirlpool. Once in the swift current the canoe became as help- 
less as a chip. It was turned this way and that, each turn head- 
ing it apparently straight for destruction. But the Indians had 
judged their position well, and though we seemed each moment in 
a worse predicament, we at last skimmed the edge of the whirl- 
pool and brought our canoe to shore just beyond its rim. 

A little farther on we came to the narrow gateway of the 
Pongo, where the entire volume of the river flows between cliffs 



20 THE ANDES OF SOUTHERN PERU 

at one point no more than fifty feet apart. Here are concentrated 
the worst rapids of the lower Urubamba. For nearly fifteen 
miles the river is an unbroken succession of rapids, and once 
within its walls the Pongo offers small chance of escape. At some 
points we were fortunate enough to secure a foothold along the 
edge of the river and to let our canoe down by ropes. .At others 
we were obliged to take chances with the current, though the great 
depth of water in most of the Pongo rapids makes them really less 
formidable in some respects than the shallow rapids up stream. 
The chief danger here lies in the rotary motion of the water at the 
sharpest bends. The effect at some places is extraordinary. A 
floating object is carried across stream like a feather and driven 
at express-train speed against a solid cliff. In trying to avoid one 
of these cross-currents our canoe became turned midstream, we 
were thrown this way and that, and at last shot through three 
standing waves that half filled the canoe. 

Below the worst rapids the Pongo exhibits a swift succession 
of natural wonders. Fern-clad cliffs border it, a bush resembling 
the juniper reaches its dainty finger-lU^e stems far out over the 
river, and the banks are heavily clad with mosses. The great 
woods, silent, impenetrable, mantle the high slopes and stretch up 
to the limits of vision. Cascades tumble from the cliff summits 
or go rippling down the long inclines of the slate beds set almost 
on edge. Finally appear the white pinnacles of limestone that hem 
in the narrow lower entrance or outlet of the Pongo. Beyond this 
passage one suddenly comes out upon the edge of a rolling forest- 
clad region, the rubber territory, the country of the great woods. 
Here the Andean realm ends and Amazonia begins. 

From the summits of the white cliffs 4,000 feet above the river 
we were in a few days to have one of the most extensive views in 
South America. The break between the Andean Cordillera and the 
hill-dotted plains of the lower Urubamba valley is almost as sharp 
as a shoreline. The rolling plains are covered with leagues upon 
leagues of dense, shadowy, fever-haunted jungle. The great river 
winds through in a series of splendid meanders, and with so broad 
a channel as to make it visible almost to the horizon. Down river 



THE RAPIDS AND CANYONS OF THE URUBAMBA 21 

from our lookout one can reach ocean steamers at Iquitos "with 
less than two weeks of travel. It is three weeks to the Pacific 
via Cuzco and more than a month if one takes the route across 
the high bleak lava-covered country which we were soon to cross 
on our way to the coast at Camana. 



CHAPTER III 



THE RUBBER FORESTS 



The white limestone cliffs at Pongo de Mainique are a bound- 
ary between two great geographic provinces (Fig. 17). Down val- 
ley are the vast river plains, drained by broad meandering rivers ; 




Fig. 17 — Regional diagram of the Eastern Andes (here the Cordillera Vilcapampa) 
and the adjacent tropical plains. For an explanation of the method of construction 
and the symbolism of the diagram see p. 51. 

up valley are the rugged spurs of the eastern Andes and their en- 
cany oned streams (Fig. 18). There are outliers of the Andes still 
farther toward the northeast where hangs the inevitable haze of 
the tropical horizon, but the country beyond them differs in no 
important respect from that immediately below the Pongo. 

The foot-path to the summit of the cliffs is too narrow and 

23 



THE RUBBER FORESTS 



23 



steep for even the most 
agile mules. It is simply 
impassable for animals 
without hands. In places 
the packs are lowered by 
ropes over steep ledges 
and men must scramble 
down from one project- 
ing root or swinging vine 
to another. In the breath- 
less jungle it is a wearing- 
task to pack in all sup- 
plies for the station be- 
low the Pongo and to 
carry out the season's 
rubber. Recently however 
the ancient track has been 
replaced by a road that 
was cut with great la- 
bor, and by much blast- 
ing, across the mountain 
barrier, and at last mule 
transport has taken the 
place of the Indian. 

In the dry season it 
is a fair and delightful 
country — that on the bor- 
der of the mountains. In 
the wet season the trav- 
eler is either actually ma- 
rooned or he must slosh 
through rivers of mud 
and water that deluge the 
trails and break the 
hearts of his beasts (Fig. 
14). Here and there a 




Fig. 18 — Index map for the nine regional 
diagrams in the pages following. A rep- 
resents Fig. 17; B, 42; C, 36; D, 32; E, 34; 
F, 25; G, 26; and H, 65. 



24 THE ANDES OF SOUTHERN PERU 

large shallow-rooted tree has come crashing doA\Ti across the 
trail and with its four feet of circumference and ten feet of 
plank buttress it is as difficult to move as a house. A new trail 
must be cut around it. A little farther on, where the valley 
wall steepens and one may look down a thousand feet of slope 
to the bed of a mountain torrent, a patch of trail has become 
soaked with water and the mules pick their way, trembling, 
across it. Two days from Yavero one of our mules went 
over the trail, and though she was finally recovered she died of 
her injuries the following night. After a month's work in the 
forest a mule must run free for two months to recover. The pack- 
ers count on losing one beast out of five for every journey into the 
forest. It is not solely a matter of work, though this is terrific; 
it is quite largely a matter of forage. In spite of its profusion 
of life (Fig. 13) and its really vast wealth of species, the tropical 
forest is all but barren of grass. Sugar cane is a fair substitute, 
but there are only a few cultivated spots. The more tender leaves 
of the trees, the young shoots of cane in the carrizo swamps, 
and the grass-like foliage of the low bamboo are the chief substi- 
tutes for pasture. But they lead to various disorders, besides re- 
quiring considerable labor on the part of the dejected peons who 
must gather them after a day's heavy work with the packs. 

Overcoming these enormous difficulties is expensive and some 
one must pay the bill. As is usual in a pioneer region, the native 
laborer pays a large part of it in unrequited toil ; the rest is paid 
by the rubber consumer. For this is one of the cases where a 
direct road connects the civilized consumer and the barbarous pro- 
ducer. What a story it could tell if a ball of smoke-cured rubber 
on a New York dock were endowed with speech — of the wet jungle 
path, of enslaved peons, of vile abuses by immoral agents, of all 
the toil and sickness that make the tropical lowland a reproach ! 

In the United States the specter of slavery haunted the na- 
tional conscience almost from the beginning of national life, and 
the ghost was laid only at the cost of one of the bloodiest wars in 
history. In other countries, as in sugar-producing Brazil, the 
freeing of the slaves meant not a war but the verge of financial 




Fig. 19. 




Fig. 20. 



Fig. 19 — Moss-draped trees in the rain forest near Abra Toeate between Rosalina 
and Pongo de Mainique. 

Fig. 20 — ^Yavero, a rubber station on the Yavero (Paucartambo) River, a tributary 
of the Urubamba. Elevation 1,600 feet (490 m.). 




Fig. 21 — Clearing in tlie tropical forest between Rosalina and Pabellon. This 

represents tlie border region wliere the forest-dwelling Machiganga Indians and tlie 

mountain Indians meet. The clearings are occupied by jMachigangas wliose chief crops 

are yuca and corn; in the extreme upper left-hand corner are grassy slopes occupied 

.by Quechua herdsmen and farmers who grow potatoes and corn. 



THE RUBBER FORESTS 25 

ruin besides a fundamental change in the social order and prob- 
lems as complex and wearisome as any that war can bring. 
Everywhere abolition was secured at frightful cost. 

The spirit that upheld the new founders of the western repub- 
lics in driving out slavery was admirable, but as much cannot be 
said of their work of reconstruction. "We like to pass over those 
dark days in our own history. In South America there has lin- 
gered from the old slave-holding days down to the present, a labor 
system more insidious than slavery, yet no less revolting in its de- 
tails, and infinitely more difficult to stamp out. It is called 
peonage ; it should be called slavery. In Bolivia, Peru, and Brazil 
it flourishes now as it ever did in the fruitful soil of the interior 
provinces where law and order are bywords and where the scarcity 
of workmen will long impel men to enslave labor when they can- 
not employ it. Peonage is slavery, though as in all slave systems 
there are many forms under which the system is worked out. We 
commonly think that the typical slave is one who is made to work 
hard, given but little food, and at the slightest provocation is tied 
to a post and brutally whipped. This is indeed the fate of many 
slaves or "peons" so-called, in the Amazon forests; but it is no 
more the rule than it was in the South before the war, for a peon 
is a valuable piece of property and if a slave raider travel five 
hundred miles through forest and jungle-swamp to capture an 
Indian you may depend upon it that he will not beat him to death 
merely for the fun of it. 

That unjust and frightfully cruel floggings are inflicted at 
times and in some places is of course a result of the lack of official 
restraint that drunken owners far from the arm of the law some- 
times enjoy. "When a man obtains a rubber concession from the 
government he buys a kingdom. Many of the rubber territories 
are so remote from the cities that officials can with great difficulty 
be secured to stay at the customs ports. High salaries must be 
paid, heavy taxes collected, and grafting of the most flagrant kind 
winked at. Often the concessionaire himself is chief magistrate 
of his kingdom by law. Under such a system, remote from all 
civilizing influences, the rubber producer himself oftentimes a law- 



26 THE ANDES OF SOUTHERN PERU 

less border character or a downright criminal, no system of gov- 
ernment would be adequate, least of all one like peonage that per- 
mits or ignores flagrant wrongs because it is so expensive to en- 
force justice. 

The peonage system continues by reason of that extraordinary 
difficulty in the development of the tropical lowland of South 
America — the lack of a labor supply. The population of Amazonia 
now numbers less than one person to the square mile. The people 
are distributed in small groups of a dozen to twenty each in scat- 
tered villages along the river banks or in concealed clearings 
reached by trails known only to the Indians. Nearly all of them 
still live in the same primitive state in which they lived at the 
time of the Discovery. In the Urubamba region a single cotton 
shirt is worn by the married men and women, while the girls 
and boys in many cases go entirely naked except for a loincloth 
or a necklace of nuts or monkeys' teeth (Fig. 23). A cane hut 
with a thatch to keep out the heavy rains is their shelter and their 
food is the yuca, sugar cane, Indian corn, bananas of many kinds, 
and fish. A patch of yuca once planted will need but the most 
trifling attention for years. The small spider monkey is their 
greatest delicacy and to procure it they will often abandon every 
other project and return at their own sweet and belated will. 

In the midst of this natural life of the forest-dwelling Indian 
appears the rubber man, who, to gather rubber, must have rubber 
"pickers." If he lives on the edge of the great Andean Cordil- 
lera, laborers may be secured from some of the lower valleys, but 
they must be paid well for even a temporary stay in the hot and 
unhealthful lowlands. Farther out in the great forest country the 
plateau Indians will not go and only the scattered tribes remain 
from which to recruit laborers. For the nature-life of the Indian 
what has the rubber gatherer to offer? Money? The Indian uses 
it for ornament only. When I once tried with money to pay an 
Indian for a week's services he refused it. In exchange for his 
severe labor he wanted nothing more than a fish-hook and a ring, 
the two costing not more than a penny apiece ! When his love for 
ornament has once been gratified the Indian ceases to work. His 



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cj 






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THE RUBBER FORESTS 27 

food and shelter and clothing are of the most primitive kind, but 
they are the best in the world for him because they are the only 
kind he has known. So where money and finery fail the lash comes 
in. The rubber man says that the Indian is lazy and must be 
made to work; that there is a great deal of work to be done and 
the Indian is the only laborer who can be found; that if rubber 
and chocolate are produced the Indian must be made to produce 
them; and that if he will not produce them for pay he must be 
enslaved. 

It is a law of the rubber country that when an Indian falls into 
debt to a white man he must work for the latter until the debt is 
discharged. If he runs away before the debt is canceled or if he 
refuses to work or does too little work he may be flogged. Under 
special conditions such laws are wise. In the hands of the rubber 
men they are the basis of slavery. For, once the rubber interests 
begin to suffer, the promoters look around for a chance to capture 
free Indians. An expedition is fitted out that spends weeks ex- 
ploring this river or that in getting on the track of unattached In- 
dians. When a settlement is found the men are enslaved and taken 
long distances from home finally to reach a rubber property. 
There they are given a corner of a hut to sleep in, a few cheap 
clothes, a rubber-picking outfit, and a name. In return for these 
articles the unwilling Indian is charged any fanciful price that 
comes into the mind of his "owner," and he must thereupon work 
at a per diem wage also fixed by the owner. Since his obligations 
increase with time, the Indian may die over two thousand dollars 
in debt ! 

Peonage has left frightful scars upon the country. In some 
places the Indians are fugitives, cultivating little farms in se- 
creted places but visiting them only at night or after carefully re- 
connoitering the spot. They change their camps frequently and 
make their way from place to place by secret trails, now spending 
a night or two under the shelter of a few palm leaves on a sand- 
bar, again concealing themselves in almost impenetrable jungle. 
If the hunter sometimes discovers a beaten track he follows it only 
to find it ending on a cliff face or on the edge of a lagoon where 



28 THE ANDES OF SOUTHERN PERU 

concealment is perfect. There are tribes that shoot the white man 
at sight and regard him as their bitterest enemy. Experience has 
led them to believe that only a dead white is a good white, revers- 
ing our saying about the North American Indian; and that even 
when he comes among them on peaceful errands he is likely to 
leave behind him a trail of syphilis and other venereal diseases 
scarcely less deadly than his bullets. 

However, the peonage system is not hideous everywhere and in 
all its aspects. There are white owners who realize that in the 
long run the friendship of the Indians is an asset far greater than 
unwilling service and deadly hatred. Some of them have indeed 
intermarried with the Indians and live among them in a state but 
little above savagery. In the Mamore country are a few o'SATiers 
of original princely concessions who have gro'wn enormously 
wealthy and yet who continue to live a primitive life among their 
scores of illegitimate descendants. The Indians look upon then; 
as benefactors, as indeed many of them are, defending the Indians 
from ill treatment by other whites, giving them clothing and orna- 
ments, and exacting from them only a moderate amount of labor. 
In some cases indeed the whites have gained more than simple 
gratitude for their humane treatment of the Indians, some of 
whom serve their masters with real devotion. 

When the "rubber barons" wish to discourage investigation 
of their system they invite the traveler to leave and he is given 
a canoe and oarsmen with which to make his way out of the dis- 
trict. Eefusal to accept an offer of canoes and men is a declara- 
tion of war. An agent of one of the London companies accepted 
such a challenge and was promptly told that he Avould not leave 
the territory alive. The threat would have held true in the case 
of a less skilful man. Though Indians slept in the canoes to pre- 
vent their seizure, he slipped past the guards in the night, swam 
to the opposite shore, and there secured a canoe within which ho 
made a difficult journey down river to the nearest post where food 
and an outfit could be secured. 

A few companies operating on or near the border of the Cordil- 
lera have adopted a normal labor system, dependent chiefly upon 



THE RUBBER FORESTS 29 

people from the plateau and upon the thoroughly willing assist- 
ance of well-paid forest Indians. The Compaiiia Gomera de 
Mainique at Puerto Mainique just below the Pongo is one of these 
and its development of the region without violation of native 
rights is in the highest degree praiseworthy. In fact the whole 
conduct of this company is interesting to a geographer, as it 
reflects at every point the physical nature of the country. 

The government is eager to secure foreign capital, but in east- 
ern Peru can offer practically nothing more than virgin wealth, 
that is, land and the natural resources of the land. There are no 
roads, virtually no trails, no telegraph lines, and in most cases no 
labor. Since the old Spanish grants ran at right angles to the 
river so as to give the owners a cross-section of varied resources, 
the up-river plantations do not extend down into the rubber coun- 
try. Hence the more heavily forested lower valleys and plains 
are the property of the state. A man can buy a piece of land 
down there, but from any tract within ordinary means only a 
primitive living can be obtained. The pioneers therefore are the 
rubber men who produce a precious substance that can stand the 
enormous tax on production and transportation. They do not 
want the land — only the exclusive right to tap the rubber trees 
upon it. Thus there has arisen the concession plan whereby a 
large tract is obtained under conditions of money payment or of 
improvements that will attract settlers or of a tax on the export. 

The "caucho" or poorer rubber of the Urubamba Valley be- 
gins at 3,000 feet (915 m.) and the "hevea" or better class is a 
lower-valley and plains product. The rubber trees thereabouts 
produce 60 grams (2 ozs.) of dry rubber each week for eight 
months. After yielding rubber for this length of time a tree is 
allowed to rest four or five years. "Caucho" is produced from 
trees that are cut down and ringed with machetes, but it is from 
fifty to sixty cents cheaper owing to the impurities that get into 
it. The wood, not the nut, of the Palma carmona is used for smok- 
ing or "curing" the rubber. The government had long been 
urged to build a road into the region in place of the miserable 
track — absolutely impassable in the wet season — that heretofore 



30 THE ANDES OF SOUTHERN PERU 

constituted the sole means of exit. About ten years ago Seuor 
Eobledo at last built a government trail from Eosalina to Yavero 
about 100 miles long. While it is a wretched trail it is better than 
the old one, for it is more direct and it is better drained. In the 
wet season parts of it are turned into rivers and lakes, but it is 
probably the best that could be done "with the small grant of twenty 
thousand dollars. 
^ With at least an improvement in the trail it became possible 
for a rubber company to induce cargadores or packers to trans- 
port merchandise and rubber and to have a fair chance of success. 
Whereupon a rubber company was organized which obtained a con- 
cession of 28,000 hectares (69,188 acres) of land on condition that 
the company finish a road one and one-half meters wide to the 
Pongo, connecting with the road which the government had ex- 
tended to Yavero. The land given in payment was not continuous 
but was selected in lots by the company in such a way as to secure 
the best rubber trees over an area several times the size of the 
concession. The road was finished by William Tell after four 
years' work at a cost of about seventy-five thousand dollars. The 
last part of it was blasted out of slate and limestone and in 1912 
the first pack train entered Puerto Mainique. 

The first rubber was taken out in November, 1910, and produc- 
tive possibilities proved by the collection of 9,000 kilos (19,841 
pounds) in eight months. 

If a main road were the chief problem of the rubber company 
the business would soon be on a paying basis, but for every mile 
of road there must be cut several miles of narrow trail (Fig. 14), 
as the rubber trees grow scattered about — a clump of a half dozen 
here and five hundred feet farther on another clump and only scat- 
tered individuals between. Furthermore, about twenty-five years 
ago rubber men from the Ucayali came up here in launches and 
canoes and cut down large numbers of trees within reach of the 
water courses and by ringing the trunks every few feet \\\ih 
machetes "bled" them rapidly and thus covered a large territory 
in a short time, and made huge sums of money when the price of 
rubber was high. Only a few of the small trees that were left 



THE RUBBER FORESTS 31 

are now mature. These, the mature trees that were overlooked, 
and the virgin stands farther from the rivers are the present 
sources of rubber. 

In addition to the trails small cabins must be built to shelter 
the hired laborers from the plateau, many of whom bring along 
their women folk to cook for them. The combined expense to a 
company of these necessary improvements before production can 
begin is exceedingly heavy. There is only one alternative for the 
prospective exploiter : to become a vagrant rubber gatherer. With 
tents, guns, machetes, cloth, baubles for trading, tinned food for 
emergencies, and with pockets full of English gold parties have 
started out to seek fortunes in the rubber forests. If the friend- 
ship of a party of Indians can be secured by adequate gifts large 
amounts of rubber can be gathered in a short time, for the Indians 
know where the rubber trees grow. On the other hand, many for- 
tunes have been lost in the rubber country. Some of the tribes 
have been badly treated by other adventurers and attack the new- 
comers from ambush or gather rubber for a while only to over- 
turn the canoe in a rapid and let the river relieve them of selfish 
friends. 

The Compania Gomera de Mainique started out by securing the 
good-will of the forest Indians, the Machigangas. They come 
and go in friendly visits to the port at Yavero. If one of them is 
sick he can secure free medicine from the agent. If he wishes 
goods on credit he has only to ask for them, for the agent knows 
that the Indian's sense of fairness will bring him back to work 
for the company. Without previous notice a group of Indians 
appears : 

"We owe," they announce. 

"Grood," says the agent, "build me a house." 

They select the trees. Before they cut them down they address 
them solemnly. The trees must not hold their destruction against 
the Indians and they must not try to resist the sharp machetes. 
Then the Indians set to work. They fell a tree, bind it with light 
ropes woven from the wild cotton, and haul it to its place. That 
is all for the day. They play in the sun, do a little hunting, or 



32 THE ANDES OF SOUTHERN PERU 

look over the agent's house, touching everything, tallving little, 
exclaiming much. They dip their wet fingers in the sugar bowl and 
taste, turn salt out upon their hands, hold colored solutions from 
the medicine chest up to the light, and puU out and push in the 
corks of the bottles. At the end of a month or two the house is 
done. Then they gather their women and babies together and saj^ : 

"Now we go," without asking if the work corresponds with the 
cost of the articles they had bought. Their judgment is good how- 
ever. Their work is almost always more valuable than the arti- 
cles. Then they shake hands all around. 

"We will come again," they say, and in a moment have disap- 
peared in the jungle that overhangs the trail. 

With such labor the Compaiiia Gomera de Mainique can do 
something, but it is not much. The regular seasonal tasks of road- 
building and rubber-picking must be done by imported labor. This 
is secured chiefly at Abancay, where live groups of plateau In- 
dians that have become accustomed to the warm climate of the 
Abancay basin. They are employed for eight or ten months at an 
average rate of fifty cents gold per day, and receive in addition 
only the simplest articles of food. 

At the end of the season the gang leaders are paid a gratifica- 
cion, or bonus, the size of which depends upon the amount of rub- 
ber collected, and this in turn depends upon the size of the gang 
and the degree of willingness to work. In the books of the com- 
pany I saw a record of gratificaciones running as high as $600 
in gold for a season's work. 

Some of the laborers become sick and are eared for by the 
agent until they recover or can be sent back to their homes. Most 
of them have fever before they return. 

The rubber costs the company two soles ($1.00) produced at 
Yavero. The two weeks' transportation to Cuzco costs three and 
a half soles ($1.75) per twenty-five pounds. The exported rubber, 
known to the trade as Mollendo rubber, in contrast to the finer 
"Para" rubber from the lower Amazon, is shipped to Hamburg. 
The cost for transportation from port to port is $24.00 per Eng- 
lish ton (1,016 kilos). There is a Peruvian tax of 8 per cent of 



THE RUBBER FORESTS 33 

the net value in Europe, and a territorial tax of two soles ($1.00) 
per hundred pounds. All supplies except the few vegetables 
grown on the spot cost tremendously. Even dynamite, hoes, cloth- 
ing, rice — to mention only a few necessities — must pay the heavy 
cost of transportation after imposts, railroad and ocean freight, 
storage and agents' percentages are added. The effect of a dis- 
turbed market is extreme. When, in 1911, the price of rubber fell 
to $1.50 a kilo at Hamburg the company ceased exporting. When it 
dropped still lower in 1912 production also stopped, and it is stiU 
doubtful, in view of the growing competition of the East-Indian 
plantations with their cheap labor, whether operations "will ever be 
resumed. Within three years no less than a dozen large com- 
panies in eastern Peru and Bolivia have ceased operations. In one 
concession on the Madre de Dios the withdrawal of the agents and 
laborers from the posts turned at last into flight, as the forest 
Indians, on learning the company's policy, rapidly ascended the 
river in force, committing numerous depredations. The great 
war has also added to the difficulties of production. 

Facts like these are vital in the consideration of the future of 
the Amazon basin and especially its habitability. It was the 
dream of Humboldt that great cities should arise in the midst of 
the tropical forests of the Amazon and that the whole lowland 
plain of that river basin should become the home of happy mil- 
lions. Humboldt's vision may have been correct, though a hun- 
dred years have brought us but little nearer its realization. Now, 
as in the past four centuries, man finds his hands too feeble to con- 
trol the great elemental forces which have shaped history. The 
most' he can hope for in the next hundred years at least is the 
ability to dodge Nature a little more successfully, and here and 
there by studies in tropical hygiene and medicine, by the substi- 
tution of water-power for human energy, to carry a few of the out- 
posts and prepare the way for a final assault in the war against 
the hard conditions of climate and relief. We hear of the Madeira- 
Mamore railroad, 200 miles long, in the heart of a tropical forest 
and of the commercial revolution it will bring. Do we realize that 
the forest which overhangs the rails is as big as the whole plain 



34 THE ANDES OF SOUTHERN PERU 

between tlie Rockies and the Appalachians, and that the proposed 
line would extend only as far as from St. Louis to Kansas City, 
or from Galveston to New Orleans? 

Even if twenty whites were eager to go where now there is but 
one reluctant pioneer, we should still have but a halting develop- 
ment on account of the scarcity of labor. When, three hundred 
years ago, the Isthmus of Panama stood in his way, Gomara 
wrote to his king: "There are mountains, but there are also 
hands," as if men could be conjured up from the tropical jungle. 
From that day to this the scarcity of labor has been the chief dif- 
ficulty in the lowland regions of tropical South America. Even 
when medicine shall have been advanced to the point where resi- 
dence in the tropics can be made safe, the Amazon basin will lack 
an adequate supply of workmen. Where Humboldt saw thriving 
cities, the population is still less than one to the square mile in 
an area as large as fifteen of our Mississippi Valley states. We 
hear much about a rich soil and little about intolerable insects j 
the climate favors a good growth of vegetation, but a man can 
starve in a tropical forest as easily as in a desert; certain tribu- 
taries of the Negro are bordered by rich rubber forests, yet not 
a single Indian hut may be found along their banks. Will men 
of the white race dig up the rank vegetation, sleep in grass ham- 
mocks, live in the hot and humid air, or will they stay in the cooler 
regions of the north and south'? Will they rear children in the 
temperate zones, or bury them in the tropics ? 

What Gorgas did for Panama was done for intelligent people. 
Can it be duplicated in the case of ignorant and stupid laborers? 
Shall the white man with wits fight it out with Nature in a tropical 
forest, or fight it out with his equals under better skies ? 

The tropics must be won by strong hands of the lowlier classes 
who are ignorant or careless of hygiene, and not by the khaki-clad 
robust young men like those who work at Panama. Tropical medi- 
cine can do something for these folk, but it cannot do much. And 
we cannot surround every laborer's cottage with expensive 
screens, oiled ditches, and well-kept lawns. There is a practical 
optimism and a sentimental optimism. The one is based on facts ; 



THE RUBBER FORESTS 35 

the other on assumptions. It is pleasant to think that the tropical 
forest may be conquered. It is nonsense to say that we are now 
conquering it in any comprehensive and permanent way. That 
sort of conquest is still a dream, as when Humboldt wrote over a 
hundred years ago. 



CHAPTER IV 
THE FOREST INDIANS 

The people of a tropical forest live under conditions not unlike 
those of the desert. The Sahara contains 2,000,000 persons within 
its borders, a density of one-half to the square mile. This is al- 
most precisely the density of population of a tract of equivalent 
size in the lowland forests of South America. Like the oases 
groups in the desert of aridity are the scattered groups along the 
river margins of the forest. The desert trails run from spring to 
spring or along a valley floor where there is seepage or an inter- 
mittent stream; the rivers are the highways of the forest, the 
flowing roads, and away from them one is lost in as true a sense 
as one may be lost in the desert. 

A man may easily starve in the tropical forest. Before start- 
. ing on even a short journey of two or three days a forest Indian 
stocks his canoe with sugar cane and yuca and a little parched 
com. He knows the settlements as well as his desert brother 
knows the springs. The Pahute Indian of Utah lives in the irri- 
gated valleys and makes annual excursions across the desert to 
the distant mountains to gather the seeds of the nut pine. The 
Machiganga lives in the hills above the Urubamba and annually 
comes down through the forest to the river to fish during the dry 
season. 

The Machigangas are one of the important tribes of the Ama- 
zon basin. Though they are dispersed to some extent upon the 
plains their chief groups are scattered through the heads of a 
large number of valleys near the eastern border of the Andes. 
Chief among the valleys they occupy are the Pilcopata, Tono, 
Pini-pini, Yavero, Yuyato, Shirineiri, Ticumpinea, Timpia, and 
Camisea (Fig. 203). Ii;i their distribution, in their relations with 
-4Pmi other, in their manner of life, and to some extent in their 
personal traits, they display characteristics strikingly like those 

36 



THE FOREST INDIANS 37 

seen in desert peoples. Though the forest that surrounds them 
suggests plenty and the rivers the possibility of free movement 
with easy intercourse, the struggle of life, as in the desert, is 
against useless things. Travel in the desert is a conflict with heat 
and aridity; but travel in the tropic forest is a struggle against 
space, heat, and a superabundant and all but useless vegetation. 

The Machigangas are one of the subtribes of the Campas In- 
dians, one of the most numerous groups in the Amazon Valley. It 
is estimated that there are in all about 14,000 to 16,000 of them. 
Each subtribe numbers from one to four thousand, and the terri- 
tory they occupy extends from the limits of the last plantations — 
for example, Eosalina in the Urubamba Valley — downstream be- 
yond the edge of the plains. Among them three subtribes are still 
hostile to the whites : the Cashibos, the Chonta Campas, and the 
Campas Bravos. 

In certain cases the Cashibos are said to be anthropophagous, 
in the belief that they will assume the strength and intellect of 
those they eat. This group is also continuously at war with its 
neighbors, goes naked, uses stone hatchets, as in ages past, be- 
cause of its isolation and unfriendliness, and defends the entrances 
to the tribal huts with dart and traps. The Cashibos are diminish- 
ing in numbers and are now scattered through the valley of the 
Oran Pajonal, the left bank of the Pachitea, and the Pampa del 
Sacramento.^ 

The friendliest tribes live in the higher valley heads, where 
they have constant communication with the whites. The use of the 
bow and arrow has not, however, been discontinued among them, 
in spite of the wide introduction of the old-fashioned muzzle-load- 
ing shotgun, which they prize much more highly than the latest 
rifle or breech-loading shotgun because of its simplicity and cheap- 

' The Cashibos of the Pachitea are the tribe for whom the Piros besought Herndon 
to produce "some great and infectious disease" which could be carried up the river 
and let loose amongst them (Herndon, Exploration of the Valley of the Amazon, 
Washington, 1854, Vol. 1, p. 196). This would-be artfulness suggests itself as some- 
thing of a match against the cunning of the Cashibos whom rumor reports to imitate 
the sounds of the forest animals with such skill as to betray into their handjhl^^ 
hunters of other tribes (see von Tschudi, Travels in Peru During the Years je38^S^^ 
-translated from the German by Thomasina Ross, New York, 1849, p. 404). »— ~ 



38 THE ANDES OF SOUTHERN PERU 

ness. Accidents are frequent among them owing to the careless 
use of fire-arms. On our last day's journey on the Urubamba 
above the mouth of the Timpia one of our Indian boys dropped his 
canoe pole on the hammer of a loaded shotgun, and not only shot 
his own fingers to pieces, but gravely Avounded his father (Fig. 2). 
In spite of his suffering the old chief directed our work at the 
canoe and even was able to tell us the location of the most favora- 
ble channel. Though the night that followed was as black as ink, 
with even the stars obscured by a rising storm, his directions 
never failed. We poled our way up five long rapids without sjie- 
cial difficulties, now working into the lee of a rock whose location 
he knew within a few yards, now paddling furiously across the 
channel to catch the upstream current of an eddy. 

The principal groups of Machigangas live in the middle Uru- 
bamba and its tributaries, the Yavero, Yuyato, Shirineiri, Ticum- 
pinea, Timpia, Pachitea, and others. There is a marked difference 
in the use of the land and the mode of life among the different 
groups of this subtribe. Those who live in the lower plains and 
river "playas," as the patches of flood plain are called, have a sin- 
gle permanent dwelling and alternately fish and hunt. Those that 
live on hill farms have temporary reed huts on the nearest sand- 
bars and spend the best months of the dry season — April to Oc- 
tober — in fishing and drying fish to be carried to their mountain 
homes (Fig. 21). Some families even duplicate chacras or farms 
at the river bank and grow yuca and sugar cane. In latter years 
smallpox, malaria, and the rubber hunters have destroyed many 
of the river villages and driven the Indians to permanent resi- 
dence in the hills or, where raids occur, along secret trails to hid- 
den camps. 

Their system of agriculture is strikingly adapted to some im- 
portant features of tropical soil. The thin hillside soils of the 
region are but poorly stocked with humus, even in their virgin 
condition. Fallen trees and foliage decay so quickly that the layer 
of forest mold is exceedingly thin and the little that is incor- 
porated in the soil is confined to a shallow surface layer. To meet 
these special conditions the Indian makes new clearings by gir- 



THE FOREST INDIANS 39 

dling and burning the trees. When the soil becomes worn out and 
the crops diminish, the old clearing is abandoned and allowed to 
revert to natural growth and a new farm is planted to corn and 
yuca. The population is so scattered and thin that the land assign- 
ment system current among the plateau Indians is not practised 
among the Machigangas. Several families commonly live together 
and may be separated from their nearest neighbors by many miles 
of forested mountains. The land is free for all, and, though some 
heavy labor is necessary to clear it, once a small patch is cleared 
it is easy to extend the tract by limited annual cuttings. Local 
tracts of naturally unforested land are rarely planted, chiefly be- 
cause the absence of shade has allowed the sun to burn out the 
limited humus supply and to prevent more from accumulating. 
The best soil of the mountain slopes is found where there is the 
heaviest growth of timber, the deepest shade, the most humus, and 
good natural drainage. It is the same on the playas along the 
river ; the recent additions to the flood plain are easy to cultivate, 
but they lack humus and a fine matrix which retains moisture 
and prevents drought or at least physiologic dryness. Here, too, 
the timbered areas or the cane swamps are always selected for 
planting. 

The traditions of the Machigangas go back to the time of the 
Inca conquest, when the forest Indians, the "Antis," were subju- 
gated and compelled to pay tribute.- When the Inca family itself 
fled from Cuzco after the Spanish Conquest and sought refuge in 
the wilderness it was to the Machiganga country that they came by 
way of the Vilcabamba and Pampaconas Valleys. Afterward came 
the Spaniards and though they did not exercise governmental au- 

" The early chronicles contain several references to Antisuyu and the Antis. 
Gareilaso de la Vega's description of the Inca conquests in Antisuyu are well knoAvn 
(Royal Commentaries of the Yncas, Book 4, Chapters 16 and 17, Hakluyt Soc. Pubis., 
1st Ser., No. 41, 1869 and Book 7, Chapters 13 and 14, No. 45, 1871). Salcaraayhua 
who also chronicles these conquests relates a legend concerning the tribute payers 
of the eastern valleys. On one occasion, he says, three hundred Antis came laden with 
gold from Opatari. Their arrival at Cuzco was coincident with a killing frost that 
ruined all the crops of the basin whence the three hundred fortunates were ordered 
with their gold to the top of the high hill of Pachatucsa (Pachatusun) and there 
buried with it (An Account of the Antiquities of Peru, Hakluyt Soc. Pubis., 1st 
Ser., No. 48, 1873). 



40 THE ANDES OF SOUTHERN PERU 

thority over the forest Indians they had close relations ■Nsith them. 
Land grants were made to white pioneers for special services or 
through sale and with the land often went the right to exploit the 
people on it. Some of the concessions were o\\Tied by people who 
for generations knew nothing save by hearsay of the Indians who 
dwelt in the great forests of the valleys. In later years they have 
been exploring their lands and establishing so-called relations 
whereby the savage ' ' buys ' ' a dollar 's worth of powder or knives 
for whatever number of dollars' worth of rubber the owner may 
care to extract from him. 

The forest Indian is still master of his lands throughout most 
of the Machiganga country. He is cruelly enslaved at the rubber 
posts, held by the loose bonds of a desultory trade at others, and 
in a few places, as at Pongo de Mainique, gives service for both 
love and profit, but in many places it is impossible to establish con- 
trol or influence. The lowland Indian never falls into the abject 
condition of his Quechua brother on the plateau. He is self-re- 
liant, proud, and independent. He neither cringes before a white 
nor looks up to him as a superior being. I was greatly impressed 
by the bearing of the first of the forest tribes I met in August, 
1911, at Santo Anato. I had built a brisk fire and was enjoying 
its comfort when La Sama returned with some Indians whom he 
had secured to clear his playa. The tallest of the lot, wearing a 
colored band of deer skin around his thick hair and a gaudy bunch 
of yellow feathers doAvn his back, came up, looked me squarely in 
the eye, and asked 
, "Tatiry payta?" (What is your name?) 

When I replied he quietly sat down by the fire, helping himself 
to the roasted corn I had prepared in the hot ashes. A few days 
later when we came to the head of a rapid I was busy sketching-in 
my topographic map and did not hear his twice repeated request 
to leave the boat while the pai'ty reconnoitered the rapid. Watch- 
ing his opportunity he came alongside from the rear — he was 
steersman — and, turning just as he was leaving the boat, gave me 
a whack in the forehead with his open palm. La Sama saw the 
motion and protested. The surly answer was : 



THE FOREST INDIANS 4.1 

"I twice asked him to get out and he didn't move. "What does 
he think we run the canoe to the bank for ? ' ' 

To him the making of a map was inexplicable ; I was merely a 
stupid white person who didn't know enough to get out of a canoe 
when told! 

The plateau Indian has been kicked about so long that all his 
independence has been destroyed. His goods have been stolen, his 
services demanded without recompense, in many places he has no 
right to land, and his few real rights are abused beyond belief. The 
difference between him and the forest Indian is due quite largely 
to differences of enviroimient. The plateau Indian is agricultural, 
the forest Indian nomadic and in a hunting stage of development ; 
the unf orested plateau offers no means for concealment of person 
or property, the forest offers hidden and difficult paths, easy 
means for concealment, for ambush, and for wide dispersal of an 
afflicted tribe. The brutal white of the plateau follows altogether 
different methods when he finds himself in the Indian country, far 
from military assistance, surrounded by fearless savages. He 
may cheat but he does not steal, and his brutality is always care- 
fully suited to both time and place. 

The Machigangas are now confined to the forest, but the limits 
of their territory were once farther upstream, where they were in 
frequent conflict with the plateau Indians. As late as 1835, ac- 
cording to General Miller,' they occupied the land as far upstream 
as the "Encuentro" (junction) of the Urubamba and the Yanatili 
(Fig. 53). Miller likewise notes that the Chuntaguirus, "a 
superior race of Indians" who lived "toward the Maranon," 
came up the river "200 leagues" to barter with the people 
thereabouts. / 

"They bring parrots and other birds, monkeys, cotton robes 
white and painted, wax balsams, feet of the gran bestia, feather 
ornaments for the head, and tiger and other skins, which they ex- 
change for hatchets, knives, scissors, needles, buttons, and any 
sort of glittering bauble." 

" Notice of a Journey to the Northward and also to the Northeastward of Cuzco. 
Royal Geog. Soc. Journ., Vol. 6, 1836, pp. 174-186. 



42 THE ANDES OF SOUTHERN PERU 

On their yearly excursions they traveled in a band numbering 
from 200 to 300, since at the mouth of the Paucartambo (Yavero) 
they were generally set upon by the Pucapacures. The journey 
upstream required three months; with the current they returned 
home in fifteen days. 

Their place of meeting at the mouth of the Yanatili was a 
response to a long strip of grassland that extends down the deep 
and dry Urubamba Valley, as shown in Figs. 5.3-B and 55. The 
wet forests, in which the Machigangas live, cover the hills back 
of the valley plantations; the belt of dry grassland terminates 
far within the general limits of the red man's domain and only 
2,000 feet above the sea. It is in this strip of low grassland that 
on the one hand the highland and valley dwellers, and on the other 
the Indians of the hot forested valleys and the adjacent lowland 
found a convenient place for barter. The same physiogi-aphic 
features are repeated in adjacent valleys of large size that drain 
the eastern aspect of the Peruvian Andes, and in each case they 
have given rise to the periodic excursions of the trader. 

These annual journeys are no longer made. The planters have 
crept down valley. The two best playas below Eosalina are now 
being cleared. Only a little space remains between the lowest val- 
ley plantations and the highest rubber stations. Furthermore, the 
Indians have been enslaved by the rubber men from the Ucayali. 
The Machigangas, many of whom are runaway peons, vnW no 
longer take cargoes down valley for fear of recapture. They have 
the cautious spirit of fugitives except in their remote valleys. 
There they are secure and now and then reassert their old spirit 
when a lawless trader tries to browbeat them into an unprofitable 
trade. Also, they are yielding to the alluring call of the planter. 
At Santo Anato they are clearing a playa in exchange for am- 
munition, machetes, brandy, and baubles. They no longer make 
annual excursions to get these things. They have only to call at 
the nearest plantation. There is always a wolf before the door of 
the planter — the lack of labor. Yet, as on every frontier, he turns 
wolf himself when the lambs come, and without shame takes a 
week's work for a penny mirror, or, worse still, supplies them 



THE FOREST INDIANS 43 

with firewater, for that will surely bring them back to him. Since 
this is expensive they return to their tribal haunts with nothing 
except a debauched spirit and an appetite from which they can- 
not run away as they did from their task masters in the rubber 
forest. Hence the vicious circle: more brandy, more labor; more 
labor, more cleared land; more cleared land, more brandy; more 
brandy, less Indian. But by that time the planter has a large 
sugar estate. Then he can begin to buy the more expensive 
plateau labor, and in turn debauch it. 

Nature as well as man works against the scattered tribes of 
Machigangas and their forest kinsmen. Their country is exceed- 
ingly broken by ramifying mountain spurs and valleys overhung 
with cliffs or bordered by bold, wet, fern-clad slopes. It is 
useless to try to cut your way by a direct route from one 
point to another. The country is mantled with heavy forest. 
You must follow the valleys, the ancient trails of the people. The 
larger valleys offer smooth sand-bars along the border of which 
canoes may be towed upstream, and there are little cultivated 
places for camps. But only a few of the tribes live along them, 
for they are also more accessible to the rubbermen. The smaller 
valleys, difficult of access, are more secure and there the tribal rem- 
nants live today. While the broken country thus offers a refuge 
to fugitive bands it is the broken country and its forest cover that 
combine to break up the population into small groups and keep 
them in an isolated and quarrelsome state. Chronic quarreling 
is not only the product of mere lack of contact. It is due to many 
causes, among which is a union of the habit of migration and 
divergent tribal speech. Every tribe has its own peculiar words 
in addition to those common to the group of tribes to which it be- 
longs. Moreover each group of a tribe has its distinctive words. 
I have seen and used carefully prepared vocabularies — no two of 
which are alike throughout. They serve for communication with 
only a limited number of families. These peculiarities increase 
as experiences vary and new situations call for additions to or 
changes in their vocabularies, and when migrating tribes meet 
their speech may be so unlike as to make communication difficult. 



4.4 THE ANDES OF SOUTHERN PERU 

Thus arise suspicion, misunderstanding, plunder, and chronic war. 
Had they been a united people their defense of their rough coun- 
try might have been successful. The tribes have been divided and 
now and again, to get firearms and ammunition mth which to raid 
a neighbor, 3. tribe has joined its fortunes to those of vagrant rub- 
ber pickers only to find in time that its women were debased, its 
members decimated by strange and deadly diseases, and its old 
morality undermined by an insatiable desire for strong drink.'' 
The Indian loses whether with the white or against him. 

The forest Indian is held by his environment no less strongly 
than the plateau Indian. We hear much about the restriction of 
the plateau dweller to the cool zone in which the llama may live. 
As a matter of fact he lives far below the cool zone, where he no 
longer depends upon the llama but rather upon the mule for trans- 
port. The limits of his range correspond to the limits of the 
grasslands in the dry valley pockets already described (p. 42), or 
on the drier mountain slopes below the zone of heaviest rainfall 
(Fig. 54). It is this distribution that brought him into such in- 
timate contact with the forest Indian. The old and dilapidated 
coca terraces of the Quechuas above the Yanatili almost overlook 
the forest patches where the Machigangas for centuries built their 
rude huts. A good deal has been written about the attempts of 
the Incas to extend their rule into this forest zone and about the 
failure of these attempts on account of the tropical climate. But 
the forest Indian was held by bonds equally secure. The cold cli- 
mate of the plateau repelled him as it does today. His haunts are 
the hot valleys where he need wear only a wild-cotton shirt or 
where he may go naked altogether. That he raided the lands of 
the plateau Indian is certain, but he could never displace him. 
Only along the common borders of their domains, where the 
climates of two zones merged into each other, could the forest 
Indian and the plateau Indian seriously dispute each other's 

* Walle states (Le Pgrou Economique, Paris, 1907, p. 297) that the Conibos, a 
tribe of the Ucayali, make annual correrias or raids during the months of July, 
August, and September, that is during the season of low water. 0\-er seven hundred 
canoes are said to participate and the captives secured are sold to rubber exploiters, 
who, indeed, frequently aid in the organization of the raids. 



THE FOREST INDIANS 45 

claims to the land. Here was endless conflict but only feeble 
trade and only the most minute exchanges of cultural elements. 

Even had they been as brothers they would have had little in- 
centive to borrow cultural elements from each other. The forest 
dweller requires bow and arrow; the plateau dweller requires a 
hoe. There are fish in the warm river shallows of the forested 
zone; llamas, vicuna, vizcachas, etc., are a partial source of food 
supply on the plateau. Coca and potatoes are the chief products 
of the grassy mountain slopes ; yuca, corn, bananas, are the chief 
vegetable foods grown on the tiny cultivated patches in the forest. 
The plateau dweller builds a thick-walled hut; the valley dweller 
a cane shack. So unlike are the two environments that it would 
be strange if there had been a mixture of racial types and cul- 
tures. The slight exchanges that were made seem little more than 
accidental. Even today the Machigangas who live on the highest 
slopes own a few pigs obtained from Quechuas, but they never 
eat their flesh ; they keep them for pets merely. I saw not a single 
woolen article among the Indians along the Urubamba whereas 
Quechuas with woolen clothing were going back and forth regu- 
larly. Their baubles were of foreign make; likewise their few 
hoes, likewise their guns. 

They clear the forest about a wild-cotton tree and spin and 
weave the cotton fiber into sacks, cords for climbing trees when 
they wish to chase a monkey, ropes for hauling their canoes, shirts 
for the married men and women, colored head-bands, and fish nets. 
The slender strong bamboo is gathered for arrows. The chunta 
palm, like bone for hardness, supplies them with bows and ar- 
row heads. The brilliant red and yellow feathers of forest birds, 
also monkey bones and teeth, are their natural ornaments. Their 
life is absolutely distinct from that of their Quechua neighbors. 
Little wonder that for centuries forest and plateau Indians have 
been enemies and that their cultures are so distinct, for their 
environment everywhere calls for unlike modes of existence and 
distinct cultural development. 



CHAPTER V 
THE COUNTRY OF THE SHEPHERDS 

The lofty mountain zones of Peru, the high bordering valleys, 
and the belts of rolling plateau between are occupied by tribes of 
shepherds. In that cold, inhospitable region at the top of the 
country are the highest permanent habitations in the world — 
17,100 feet (5,210 m.) — the loftiest pastures, the greatest degree 
of adaptation to combined altitude and frost. It is here only a 
step from Greenland to Arcady. Nevertheless it is Greenland that 
has the people. Why do they shun Arcady? To the traveler from 
the highlands the fertile valleys between 5,000 and 8,000 feet (1,500 
to 2,500 m.) seem like the abode of friendly spirits to whose charm 
the highland dweller must yield. Every pack-train from valley 
to highland carries luxury in the form of fruit, coca, cacao, and 
sugar. One would think that every importation of valley products 
would be followed by a wave of migration from highland to val- 
ley. On the contrary the highland people have clung to their lofty 
pastures for unnumbered centuries. Until the Conquest the last 
outposts of the Incas toward the east were the grassy ridges that 
terminate a few thousand feet below the timber line. 

In this natural grouping of the people where does choice or 
blind prejudice or instinct leave off? Where does necessity be- 
gin? There are ansAvers to most of these questions to be found 
in the broad field of geographic comparison. But before we begin 
comparisons we must study the individual facts upon which they 
rest. These facts are of almost every conceivable variety. They 
range in importance from a humble shepherd's stone corral on a 
mountain slope to a thickly settled mountain basin. Their in- 
terpretation is to be sought now in the soil of rich playa lands, 
now in the fixed climatic zones and rugged relief of deeply dis- 
sected, lofty highlands in the tropics. Some of the controlling 
factors are historical, others economic; still other factors have 

46 



THE COUNTRY OF THE SHEPHERDS 47 

exerted their influence through obscure psychologic channels al- 
most impossible to trace. The why of man's distribution over the 
earth is one of the most complicated problems in natural science, 
and the solution of it is the chief problem of the modern 
geographer. 

At first sight the mountain people of the Peruvian Andes seem 
to be uniform in character and in mode of life. The traveler's 
first impression is that the same stone-walled, straw-thatched type 
of hut is to be found everywhere, the same semi-nomadic life, the 
same degrees of poverty and filth. Yet after a little study the 
diversity of their lives is seen to be, if not a dominating fact, at 
least one of surprising importance. Side by side with this di- 
versity there runs a corresponding diversity of relations to their 
physical environment. Nowhere else on the earth are greater phys- 
ical contrasts compressed within such small spaces. If, there- 
fore, we accept the fundamental theory of geography that there is 
a general, necessary, varied, and complex relation between man 
and the earth, that theory ought here to find a really vast num- 
ber of illustrations. A glance at the accompanying figures dis- 
closes the wide range of relief in the Peruvian Andes. The cor- 
responding range in climate and in life therefore furnishes an am- 
ple field for the application of the laws of human distribution. 

In analyzing the facts of distribution we shall do well to begin 
with the causes and effects of migration. Primitive man is in no 
small degree a wanderer. His small resources often require him 
to explore large tracts. As population increases the food quest 
becomes more intense, and thus there come about repeated emigra- 
tions which increase the food supply, extend its variety, and draw 
the pioneers at last into contact with neighboring groups. The 
farther back we go in the history of the race the clearer it becomes 
that migrations lie at the root of much of human development. 
The raid for plunder, women, food, beasts, is a persistent feature 
of the life of those primitive men who live on the border of un- 
like regions. 

The shepherd of the highland and the forest hunter of the 
plains perforce range over vast tracts, and each brings back to the 



48 THE ANDES OF SOUTHERN PERU 

home group news that confirms the tribal choice of habitation or 
sets it in motion toward a more desirable place. Superstitions 
may lead to flight akin to migration. Epidemics may be inter- 
preted as the work of a malignant spirit from which men must flee. 
War may drive a defeated group into the fastnesses of a moun- 
tain forest where pursuit by stream or trail weakens the pursuer 
and confines his action, thereby limiting his power. Floods may 
come and destroy the cultivated spots. Want or mere desire in a 
hundred forms may lead to movement. 

Even among forest tribes long stationary the facile canoe and 
the light household necessities may easily enable trivial causes to 
develop the spirit of restlessness. Pressure of population is a 
powerful but not a general cause of movement. It may affect the 
settled groups of the desert oases, or the dense population of fer- 
tile plains that is rooted in the soil. On the other hand mere 
whims may start a nomadic group toward a new goal. Often the 
goal is elusive and the tribe turns back to the old haunts or per- 
ishes in the shock of unexpected conflict. 

In the case of both primitive societies and those of a higher 
order the causes and the results of migration are often contra- 
dictory. These will depend on the state of civilization and the ex- 
tremes of circumstance. When the desert blooms the farmer of 
the Piura Valley in northwestern Peru turns shepherd and drives 
his flocks of sheep and goats out into the short-lived pastures 
of the great pampa on the west. In dry years he sends them 
eastward into the mountains. The forest Indian of the lower Uru- 
bamba is a fisherman while the river is low and lives in a reed hut 
beside his cultivated patch of cane and yuca. When the floods 
come he is driven to the higher ground in the hills where he has 
another cultivated patch of land and a rude shelter. To be sure, 
these are seasonal migrations, yet through them the country be- 
comes better knoAvn to each new generation of men. And each 
generation supplies its pioneers, who drift into the remoter places 
where population is scarce or altogether wanting. 

Dry years and extremely dry years may have opposite effects. 
When moderate dryness prevails the results may be endurable. 



fl 


fl 


•FH 




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1) 










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lit 


tiD 


d 


-a 


-4-1 




THE COUNTRY OF THE SHEPHERDS 49 

The oases become crowded with men and beasts just when they 
can ill afford to support them. The alfalfa meadows become over- 
stocked, and cattle become lean and almost worthless. But there 
is at least bare subsistence. By contrast, if extreme and pro- 
longed drought prevails, some of the people are driven forth to 
more favored spots. At Vallenar in central Chile some of the 
workmen in extreme years go up to the nitrate pampa; in wet 
years they return. When the agents of the nitrate companies hear 
of hard times in a desert valley they offer employment to the 
stricken people. It not infrequently happens that when there are 
droughts in desert Chile there are abundant rains in Argentina 
on the other side of the Cordillera. There has therefore been for 
many generations an irregular and slight, though definite, shift- 
ing of population from one side of the mountains to the other as 
periods of drought and periods of rain alternated in the two 
regions. Some think there is satisfactory evidence to prove that 
a number of the great Mongolian emigrations took place in wet 
years when pasture was abundant and when the pastoral nomad 
found it easy to travel. On the other hand it has been urged that 
the cause of many emigrations was prolonged periods of drought 
when the choice lay between starvation and flight. It is evident 
from the foregoing that both views may be correct in spite of the 
fact that identical effects are attributed to opposite causes. 

It is still an open question whether security or insecurity is 
more favorable for the broad distribution of the Peruvian Indians 
of the mountain zone which forms the subject of this chapter. Cer- 
tainly both tend to make the remoter places better known. Tradi- 
tion has it that, in the days of intertribal conflict before the Con- 
quest, fugitives fled into the high mountain pastures and lived in 
hidden places and in caves. Life was insecure and relief was 
sought in flight. On the other hand peace has brought security 
to life. The trails are now safe. A shepherd may drive his flock 
anywhere. He no longer has any one to fear in his search for new 
pastures. It would perhaps be safe to conclude that there is 
equally broad distribution of men in the mountain pastures in time 
of peace and in time of war. There is, however, a difference in 



THE ANDES OF SOUTHERN PERU 




Fig. 25 — Regional diagram for the Maritime Cordillera to show the physical 
relations in the district where the highest habitations in the world are located. For 
location, see Fig. 20. It should be remembered that the orientation of these diagrams 
is generalized. By reference to Fig. 20 it will be seen that some portions of the 
crest of the Maritime Cordillera rmi east and west and others north and south. The 
same is true of the Cordillera Vilcapampa, Fig. 30. 



the kind of distribution. In time of peace the individual is safe 
anywhere ; in time of unrest he is safe only when isolated and vir- 
tually concealed. By contrast, the group living near the trails is 



THE COUNTRY OF THE SHEPHERDS 51 

scattered by plundering bands and war parties. The remote and 
isolated group may successfully oppose the smaller band and the 
individuals that might reach the remoter regions. The fugitive 
group would have nothing to fear from large bands, for the 
limited food supply would inevitably cause these to disintegrate 
upon leaving the main routes of travel. Probably the fullest ex- 
ploration of the mountain pastures has resulted from the alterna- 
tion of peace and war. The opposite conditions which these estab- 
lish foster both kinds of distribution ; hence both the remote group 
life encouraged by war and the individual's lack of restraint in 



IJote on regional diagrams. — For the sake of clearness I have classified the accom- 
panying facts of human distribution in the country of the shepherds and represented 
them graphically in "regional" diagrams. Figs. 17, 25, 26, 32, 34, 36, 42, 65. These 
diagrams are constructed on the principle of dominant control. Each brings out the 
factors of greatest importance in the distribution of the people in a given region. 
Furthermore, the facts are compressed within the limits of a small rectangle. This com- 
pression, though great, respects all essential relations. For example, every location on 
these diagrams has a concrete illustration but the accidental relations of the field have 
been omitted; the essential relations are preserved. Each diagram is, therefore, a 
kind of generalized type map. It bears somewhat the same relation to the facts of 
human geography that a block diagram does to physiography. The darkest shading 
represents steep snow-covered country; the next lower grade represents rough but 
snow-free country; the lightest shading represents moderate relief; unshaded parts 
represent plain or plateau. Small circles represent forest or woodland; small open- 
spaced dots, grassland. Fine alluvium is represented by small closely spaced dots; 
coarse alluvium by large closely spaced dots. 

To take an illustration. In Figure 32 we have the Apurimac region near Pasaje 
(see location map, Fig. 20). At the lower edge of the rectangle is a snow-capped 
outlier of the Cordillera Vileapampa. The belt of rugged country represents the 
lofty, steep, exposed, and largely inaccessible ridges at the mid-elevations of the 
mountains below the glaciated slopes at the heads of tributary valleys. The villages 
in the belt of pasture might well be Incahuasi and Corralpata. The floors of the 
large canyons on either hand are bordered by extensive alluvial fans. The river 
courses are sketched in a diagrammatic way only, but a map would not be different 
in its general disposition. Each location is justified by a real place with the same 
essential features and relations. In making the change there has been no alteration 
of the general relation of the alluvial lands to each other or to the highland. By 
suppressing unnecessary details there is produced a diagram whose essentials have 
simple and clear relations. When such a regional diagram is amplified by 
photographs of real conditions it becomes a sort of generalized picture of a 
large group of geographic facts. One could very well extend the method to the 
whole of South America. It would be a real service to geography to draw up a set 
of, say, twelve to fifteen regional diagrams, still further generalized, for the whole 
of the continent. As a broad classification they would serve both the specialist and 
the general student. As the basis for a regional map of South America they would 
be invaluable if worked out in sufficient detail and constructed on the indispensable 
basis of field studies. 



52 THE ANDES OF SOUTHERN PERU 

time of peace are probably in large part responsible for the pres- 
ent widespread occupation of the Peruvian mountains. 

The loftiest habitation in the world (Fig. 24) is in Peru. Be- 
tween Antabamba and Cotahuasi occur the highest passes in the 
Maritime Cordillera. We crossed at 17,400 feet (5,300 m.), and 
three hundred feet lower is the last outpost of the Indian shep- 
herds. The snowline, very steeply canted away from the sun, is 
between 17,200 and 17,600 feet (5,240 to 5,360 m.). At frequent 
intervals during the three months of winter, snowfalls during the 
night and terrific hailstorms in the late afternoon drive both shep- 
herds and flocks to the shelter of leeward slopes or steep canyon 
walls. At our six camps, between 16,000 and 17,200 feet (4,876 
and 5,240 m.), in September, 1911, the minimum temperature 
ranged from 4° to 20° F. The thatched stone hut that we passed 
at 17,100 feet and that enjoys the distinction of being the highest 
in the world was in other respects the same as the thousands of 
others in the same region. It sheltered a family of five. As we 
passed, three rosy-cheeked children almost as fat as the sheep 
about them were sitting on the ground in a corner of the corral 
playing with balls of wool. Hundreds of alpacas and sheep 
grazed on the hill slopes and valley floor, and their tracks showed 
plainly that they were frequently driven up to the snowline in 
those valleys where a trickle of water supported a band of pasture. 
Less than a hundred feet below them were other huts and flocks. 

Here we have the limits of altitude and the limits of resources. 
The intervalley spaces do not support grass. Some of them are 
quite bare, others are covered with mosses. It is too high for even 
the tola bush — that pioneer of Alpine vegetation in the Andes. 
The distance^ to Cotahuasi is 75 miles (120 km.), to Antabamba 
50 miles (80 km.). Thence wool must be shipped by pack-train 
to the railroad in the one case 250 miles (400 km.) to Arequipa, in 
the other case 200 miles (320 km.) to Cuzco. Even the potatoes 
and barley, which must be imported, come from valleys several 
days' journey away. The question naturally arises why these peo- 
ple live on the rim of the world. Did they seek out these neglected 

' Distances are not taken from the map but from tlie trnil. 



THE COUNTRY OF THE SHEPHERDS 53 

pastures, or were they driven to them? Do they live here by 
choice or of necessity? The answer to these questions introduces 
two other geographic factors of prime importance, the one phys- 
ical, the other economic. 

The main tracts of lofty pasture above Antabamba cover moun- 
tain slopes and valley floor alike, but the moist valley floors supply 
the best grazing. Moreover, the main valleys have been inten- 
sively glaciated. Hence, though their sides are steep walls, their 
floors are broad and flat. Marshy tracts, periodically flooded, are 
scattered throughout, and here and there are overdeepened por- 
tions where lakes have gathered. There is a thick carpet of grass, 
also numerous huts and corrals, and many flocks. At the upper 
edge of the main zone of pasture the grasses become thin and with 
increasing altitude give out altogether except along the moist val- 
ley floors or on shoulders where there is seepage. 

If the streams head in dry mountain slopes without snow the 
grassy bands of the valley floor terminate at moderate elevations. 
If the streams have their sources in snowfields or glaciers there is 
a more uniform run-off, and a ribbon of pasture may extend to the 
snowline. To the latter class belong the pastures that support 
these remote people. 

In the case of the Maritime Andes the great elevation of the 
snowline is also a factor. K, in Figure 25, we think of the snow- 
line as at the upper level of the main zone of pasture then we 
should have the conditions shown in Figure 36, where the limit of 
general, not local, occupation is the snowline, as in the Cordillera 
Vilcapampa and between Chuquibambilla and Antabamba. 

A third factor is the character of the soil. Large amounts of 
volcanic ash and lapilli were thrown out in the late stages of vol- 
canic eruption in which the present cones of the Maritime Andes 
were formed. The coarse texture of these deposits allows the 
ready escape of rainwater. The combination of extreme aridity 
and great elevation results in a double restraint upon vegetation. 
Outside of the moist valley floors, with their film of ground 
moraine on whose surface plants find a more congenial soil, there 
is an extremely small amount of pasture. Here are the natural 



54 THE ANDES OF SOUTHERN PERU 

grazing grounds of the fleet vicuna. They occur in hundreds, and 
so remote and little disturbed are they that near the main pass 
one may count them by the score. As we rode by, many of them 
only stared at us without taking the trouble to get beyond rifle 
shot. It is not difficult to believe that the Indians easily shoot 
great numbers in remote valleys that have not been hunted for 
years. 

The extreme conditions of life existing on these lofty plateaus 
are well shown by the readiness with which even the hardy shep- 
herds avail themselves of shelter. Wherever deep valleys bring a 
milder climate within reach of the pastures the latter are unpopu- 
lated for miles on either side. The sixty-mile stretch between 
Chuquibamba and Salamanca is "without even a single hut, though 
there are pastures superior to the ones occupied by those loftiest 
huts of all. Likewise there are no permanent homes between Sala- 
manca and Cotahuasi, though the shepherds migrate across the 
belt in the milder season of rain. Eastward and northward to- 
ward the crest of the Maritime Cordillera there are no huts 
within a day's journey of the Cotahuasi canyon. Then there is a 
group of a dozen just under the crest of the secondary range that 
parallels the main chain of volcanoes. Thence northward there 
are a number of scattered huts between 15,500 and 16,500 feet 
(4,700 and 5,000 m.), until we reach the highest habitations of all 
at 17,100 feet (5,210 m.). 

The unpopulated belts of lava plateau bordering the entrenched 
valleys are, however, as distinctly "sustenance" spaces, to use 
Penck's term, as the irrigated and fertile alluvial fans in the bot- 
tom of the valley. This is well shown when the rains come and 
flocks of llamas and sheep are driven forth from the valleys to the 
best pastures. It is equally well shoAvn by the distribution of the 
shepherds ' homes. These are not down on the warm canyon floor, 
separated by a half-day's journey from the grazing. They are in 
the intrenched tributary valleys of Figure 26 or just within the 
rim of the canyon. It is not shelter from the cold but from the 
wind that chiefly determines their location. They are also kept 
near the rim of the canyon by the pressure of the farming popu- 



THE COUNTRY OF THE SHEPHERDS 



55 



lation from below. Every hundred feet of descent from the arid 
plateau (Fig. 29) increases the water supply. Springs increase 
in number and size; likewise belts of seepage make their appear- 
ance. The gradients in many places diminish, and flattish spurs 
and shoulders interrupt the generally steep descents of the canyon 




Fig. 26 — Regional diagram to show the physical relations in the lava plateau of 
the Maritime Cordillera west of the continental divide. For location, see Fig. 20. 
Trails lead up the intrenched tributaries. If the irrigated bench (lower right corner) 
is large, a town will be located on it. Shepherds' huts are scattered about the edge 
of the girdle of spurs. There is also a string of huts in the deep sheltered head of 
each tributary. See also Fig. 29 for conditions on the valley or canj'on floor. 



wall. Every change of this sort has a real value to the farmer and 
means an enhanced price beyond the ability of the poor shepherd 
to pay. If you ask a wealthy hacendado on the valley floor (Fig. 
29), who it is that live in the huts above him, he will invariably say 
"los Indios," with a shrug meant to convey the idea of poverty 
and worthlessness. Sometimes it is "los Indios pobres," or 
merely "los pobres." Thus there is a vertical stratification of 



56 THE ANDES OF SOUTHERN PERU 

society corresponding to the superimposed strata of climate and 
land. 

At Salamanca (Fig. 62) I saw this admirably displayed under 
circumstances of unusual interest. The floor and slopes of the 
valley are more completely terraced than in any other valley I 
know of. In the photograph, Fig. 30, which shows at least 2,500 
feet of descent near the town, one cannot find a single patch of sur- 
face that is not under cultivation. The valley is simply filled "with 
people to the limit of its capacity. Practically all are Indians, but 
mth many grades of wealth and importance. When we rode out 
of the valley before daybreak, one September morning in 1911, 
there was a dead calm, and each step upward carried us into a 
colder stratum of air. At sunrise we had reached a point about 
2,000 feet above the town, or 14,500 feet (4,420 m.) above sea level. 
"We stood on the frost line. On the opposite wall of the valley the 
line was as clearly marked out as if it had been an irrigating canal. 
The light was so fully reflected from the millions of frost crystals 
above it that both the mountainside and the valley slopes were 
sparkling like a rufiled lake at sunrise. Below the frost line the 
slopes were dark or covered with yellow barley and wheat stubble 
or green alfalfa. 

It happened that the frost line was near the line of division 
between corn and potato cultivation and also near the line separat- 
ing the steep rough upper lands from the cultivable lower lands. 
Not a habitation was in sight above us, except a few scattered 
miserable huts near broken terraces, gullied by wet-weather 
streams and grown up to weeds and brush. Below us were well- 
cultivated fields, and the stock was kept in bounds by stone fences 
and corrals; above, the half -wild burros and mules roamed about 
everywhere, and only the sheep and llamas were in rude enclo- 
sures. Thus in a half hour we passed the frontier between the 
agricultural folk below the frost line and the shepherd folk above 
it. 

In a few spots the line followed an irregular course, as where 
flatter lands were developed at unusual elevations or where air 
drainage altered the normal temperature. And at one place the 




Fio. 27. 







Fig. 2S. 



Fig. 27 — Terraced valley slopes at Huaynaeotas, Cotahuasi Valley, Peru. Eleva- 
tion 11,500 feet (3,500 m.). 

Fio. 28 — The highly cultivated and thoroughly terraced floor of the Ollantaytambo 
Valley at Ollantaytambo. This is a tributary of the Urubamba; elevation, 11,000 feet. 








Fig. 29 — Cotahuasi on the floor of the Cotahuasi canyon. The even skyline of the 
background is on a rather even-topped lava plateau. The terrace on the left of the 
town is formed on limestone, which is overlain by lava Hows. A thick deposit of ter- 
raced alluvium may be seen on the valley lloor, and it is on one of the lower terraces 
that the city of Cotahuasi stands. The higher terraces are in many cases too dry for 
cultivation. The canyon is nearly 7,000 feet (2,130 m.) deep and has been cut Ihrough 
one hundred principal lava flows. 



THE COUNTRY OF THE SHEPHERDS 57 

frost actually stood on the young corn, which led us to speculate 
on the possibility of securing from Salamanca a variety of maize 
that is more nearly resistant to light frosts than any now grown 
in the United States. In the endless and largely unconscious ex- 
perimentation of these folk perched on the valley walls a result 
may have been achieved ahead of that yet reached by our pro- 
fessional experimenters. Certain it is that nowhere else in the I 
world has the potato been grown under such severe climatic con- 
ditions as in its native land of Peru and Bolivia. The hardiest 
varieties lack many qualities that we prize. They are small and 
bitter.* But at least they will grow where all except very few 
cultivated plants fail, and they are edible. Could they not be im- 
ported into Canada to push still farther northward the limits of 
cultivation? Potatoes are now grown at Forts Grood Hope and 
McPherson in the lower Mackenzie basin. Would not the hardiest 
Peruvian varieties grow at least as far north as the continental 
timber line? I believe they could be grown still farther north. 
They will endure repeated frosts. They need scarcely any cultiva- 
tion. Prepared in the Peruvian manner, as chuno, they could be 
kept all winter. Being light, the meal derived from them could 
be easily packed by hunters and prospectors. An Indian will carry 
in a pouch enough to last him a week. Why not use it north of 
the continental limit of other cultivated plants since it is the 
pioneer above the frost line on the Peruvian mountains'? 

The relation between farmer and shepherd or herdsman grows \ 
more complex where deeper valleys interrupt the highlands and — i 
mountains. The accompanying sketch, Fig. 32, represents typical 
relations, though based chiefly on the Apurimac canyon and its 
surroundings near Pasaje. First there is the snow-clad region at 
the top of the country. Below it are grassy slopes, the homes of 
mountain shepherds, or rugged mountain country unsuited for 
grazing. Still lower there is woodland, in patches chiefly, but vnih. 
a few large continuous tracts. The shady sides of the ravines and 
the mountains have the most moisture, hence bear the densest 
growths. Finally, the high country terminates in a second belt 
of pasture below the woodland. 



58 



THE ANDES OF SOUTHERN PERU 



Whenever streams descend from the snow or woodland coun- 
try there is water for the stock above and for irrigation on the 
alluvial fan below. But the spur ends dropping off abruptly sev- 




FiG. 32 — Regional diagram representing the deep canyoned country west of the 
Eastern Cordillera in the region of the Apurimae. For photograph see Fig. 94. For 
further description see note on regional diagrams, p. 51. Numbers 1, 2, and 3 corre- 
spond in position to the same numbers in Fig. 33. 



eral thousand feet have a limited area and no running streams, 
and the ground water is hundreds of feet down. There is grass 
for stock, but there is no water. In some places the stock is driven 





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THE COUNTRY OF THE SHEPHERDS 69 

back and forth every few days. In a few places water is brought 
to the stock by canal from the woodland streams above, as at 
Corralpata.^ In the same way a canal brings water to Pasaje 
hacienda from a woodland strip many miles to the west. The 
little canal in the figure is almost a toy construction a few inches 

VALLEY ZONE MOUNTAIN ZONE 



FiQ. 33 — Valley climates of the canyoned region shown in Fig. 32. 

wide and deep and conveying only a trickle of water. Yet on it 
depends the settlement at the spur end, and if it were cut the peo- 
ple would have to repair it immediately or establish new homes. 
The canal and the pasture are possible because the slopes are . 
moderate. They were formed in an earlier cycle of erosion when 
the land was lower. They are hung midway between the rough 
mountain slopes above and the steep canyon walls below (Fig. 32). 
Their smooth descents and gentle profiles are in very pleasing 
contrast to the rugged scenery about them. The trails follow them 
easily. Where the slopes are flattest, farmers have settled and 
produce good crops of corn, vegetables, and barley. Some farm- 
ers have even developed three- and four-story farms. On an al- 
luvial fan in the main valley they raise sugar cane and tropical 
and subtropical fruits ; on the flat upper slopes they produce corn ; 
in the moister soil near the edge of the woodland are fields of 
mountain potatoes; and the upper pastures maintain flocks of 

' Compare with Raimondi's description of Quiches on the left bank of the MaraSon 
at an elevation of 9,885 feet (3,013 m.) : "the few small springs scarcely suffice for 
the little patches of alfalfa and other sowings have to depend on the precarious 
rains. . . . Every drop of water is carefully guarded and from each spring a series 
of well-like basins descending in staircase fashion make the most of the scant supply." 
(El Departamento de Ancachs, Lima, 1873.) 



60 THE ANDES OF SOUTHERN PERU 

sheep. In one district this change takes place in a distance that 
may be covered in five hours. Generally it is at least a full and 
hard day's journey from one end of the series to the other. 

Wherever these features are closely associated they tend to be 
controlled by the planter in some deep valley thereabouts. Where 
they are widely scattered the people are independent, small 
groups living in places nearly inaccessible. Legally they are all 
under the control of the owners of princely tracts that take in the 
whole country, but the remote groups are left almost wholly to 
themselves. In most cases they are supposed to sell their few 
commercial products to the hacendado who nominally owns their 
land, but the administration of this arrangement is left largelj^ to 
chance. The shepherds and small farmers near the plantation ai-e 
more dependent upon the planter for supplies, and also their 
wants are more varied and numerous. Hence they pay for their 
better location in free labor and in produce sold at a discount. 

So deep are some of the main canyons, like the Apurimac and 
the Cotahuasi, that their floors are arid or semi-arid. The fortunes 
of Pasaje are tied to a narrow canal from the moist woodland and 
a tiny brook from a hollow in the valley wall. Where the water 
has thus been brought down to the arable soil of the fans there are 
rich plantations and farms. Elsewhere, however, the floor is quite 
dry and uncultivated. In small spots here and there is a little 
seepage, or a few springs, or a mere thread of water that will not 
support a plantation, wherefore there have come into existence 
the valley herdsmen and shepherds. Their intimate knowledge of 
the moist places is their capital, quite as much as are the cattle and 
sheep they own. In a sense their lands are the neglected crumbs 
from the rich man's table. So we find the shepherd from the hills 
invading the valleys just as the valley farmer has invaded the 
country of the shepherd. 

The basin type of topography calls into existence a set of rela- 
tions quite distinct from either of those we have just described. 
Figure 34 represents the main facts. The rich and comparatively 
flat floor of the basin supports most of the people. The alluvial 
fans tributary thereto are composed of fine material on their outer 



THE COUNTRY OF THE SHEPHERDS 



61 




Fig. 34 — Regional diagram to show the typical physical conditions and relations 
in an intermont basin in the Peruvian Andes. The Cuzco basin (see Fig. 37) is an 
actual illustration; it should, however, be emphasized that the diagram is not a 
" map " of that basin, for whilst conditions there have been utilized as a basis, the 
generalization has been extended to illustrate many basins. 



margin and of coarse stony waste at their heads. Hence the val- 
ley farms also extend over the edges of the fans, while only pas- 
ture or dense chaparral occupies the upper portions. Finally 



62 



THE ANDES OF SOUTHERN PERU 



there is the steep margin of the basin where the broad and moder- 
ate slopes of the highland break down to the floor of the basin. 

If a given basin lies at an elevation exceeding 14,000 feet 
(4,270 m.), there will be no cultivation, only pasture. If at 10,000 
or 11,000 feet (3,000 or 3,350 m.), there will be grain fields below 



ZONE OF STORED PRECIPITATION 

SOURCES OF BASIN STREAMS 



ZONE OF CULTIVATION 

■--LIMIT OF IRRIGATION AND--; 
I INTENSIVE CULTIVATION ' 



-LOWER LIMIT OF PERMANENTISNOW 



ZONE OF MOUNTAIN PASTURES 




Fio. 35 — Climatic cross-section showing the location of various zones of cultivation 
and pasture in a typical intermont basin in the Peruvian Andes. The thickness of 
the dark symbols on the right is proportional to the amount of each staple that is 
produced at the corresponding elevation. See also the regional diagram Fig. 34. 



and potato fields above (Figs. 34 and 35). If still lower, fruit will 
come in and finally sugar cane and many other subtropical prod- 
ucts, as at Abancay. Much will also depend upon the amount of 
available water and the extent of the pasture land. Thus the 
densely populated Cuzco basin has a vast mountain territory 
tributary to it and is itself within the limits of barley and wheat 
cultivation. Furthermore there are a number of smaller basins, like 
the Anta basin on the north, which are dependent upon its better 
markets and transportation facilities. A dominance of this kind 
is self-stimulating and at last is out of all proportion to the 
original differences of nature. Cuzco has also profited as the gate- 
way to the great northeastern valley region of the Urubamba and 
its big tributaries. All of the varied products of the subtropical 
valleys find their immediate market at Cuzco. 

The effect of this natural conspiracy of conditions has been to 
place the historic city of Cuzco in a position of extraordinary im- 
portance. Hundreds of years before the Spanish Conquest it was 
a center of far-reaching influence, the home of the powerful Inca 
kings. From it the strong arm of authority and conquest was ex- 



THE COUNTRY OF THE SHEPHERDS 63 

tended; to it came tribute of grain, wool, and gold. To one ac- 
customed to look at such, great consequences as having at least 
some ultimate connection with the earth, the situation of Cuzco 
would be expected to have some unique features. With the glori- 
ous past of that city in mind, no one can climb to the surround- 
ing heights and look down upon the fertile mountain-rimmed plain 
as at an ordinary sight (Fig. 37). The secret of those great con- 
quests lies not only in mind but in matter. If the rise of the Incas 
to power was not related to the topography and climate of the 
Cuzco basin, at least it is certain that Avithout so broad and noble 
a stage the scenes would have been enacted on a far different 
scale. 

The first Inca king and the Spanish after the Incas found here 
no mobile nomadic tribes melting away at the first touch, no 
savages hiding in forest fastnesses, but a well-rooted agricultural 
race in whose center a large city had grown up. Without a city 
and a fertile tributary plain no strong system of government could 
be maintained or could even arise. It is a great advantage in rul- 
ing to have subjects that cannot move. The agricultural Indians 
of the Andean valleys and basins, in contrast to the mobile shep- 
herd, are as fixed as the soil from which they draw their life. 

The full occupation of the pasture lands about the Cuzco basin 
is in direct relation to the advantages we have already enumer- 
ated. Every part of the region feels the pressure of population. 
Nowhere else in the Peruvian Andes are the limits between cultiva- \/ 
tion and grazing more definitely drawn than here. Moreover, 
there is today a marked difference between the types that inhabit 
highland and basin. The basin Indian is either a debauched city 
dweller or, as generally, a relatively alert farmer. The shepherds 
are exceedingly ignorant and live for the most part in a manner 
almost as primitive as at the time of the Conquest. They are shy 
and suspicious. Many of them prefer a life of isolation and rarely 
go down to the town. They live on the fringe of culture. The 
new elements of their life have come to them solely by accident 
and by what might be called a process of ethnic seepage. The 
slight advances that have been made do not happen by design, they 



64. THE ANDES OF SOUTHERN PERU 

merely happen. Put the highland shepherd in the basin and he 
would starve in competition with the basin type. Undoubtedly he 
would live in the basin if he could. He has not been driven out 
of the basin; he is kept out. 

And thus it is around the border of the Abancay basin and 
others like it. Only, the Abancay basin is lower and more \'aried 
as to resources. The Indian is here in competition with the capi- 
talistic white planter. He lives on the land by sufferance alone. 
Farther up the slopes are the farms of the Indians and above 
them are the pastures of the ignorant shepherds. Whereas the 
Indian farmer who raises potatoes clings chiefly to the edge of 
the Cuzco basin where lie the most undesirable agricultural lands, 
the Indian farmers of Abancay live on broad rolling slopes like 
those near the pass northward toward Huancarama. They are 
unusually prosperous, with fields so well cultivated and fenced, 
so clean and productive, that they remind one somewhat of the 
beautiful rolling prairies of Iowa. 

It remains to consider the special topographic features of the 
mountain environments we are discussing, in the Vilcapampa 
region on the eastern border of the Andes (Fig. 36). The Cordil- 
lera Vilcapampa is snow-crested, containing a number of fine 
white peaks like Salcantay, Soray, and Soiroccocha (Fig. 140). 
There are many small glaciers and a few that are several 
miles long. There was here in glacial times a much larger system 
of glaciers, which lived long enough to work great changes in the 
topography. The floors of the glaciated valleys were smoothed 
and broadened and their gradients flattened (Figs. 137 and 190). 
The side walls were steepened and precipitous cirques were 
formed at the valley heads. Also, there were built across the val- 
leys a number of stony morainic ridges. With all these changes 
there was, however, but little effect upon the main masses of the 
big intervalley spurs. They remain as before — bold, wind-swept, 
broken, and nearly inaccessible. 

The work of the glaciers aids the mountain people. The stony 
moraines afford them handy sizable building material for thoir 
stone huts and their numerous corrals. The thick tufts of grass 



THE COUNTRY OF THE SHEPHERDS 



65 




Fig. 36 — Regional diagram for the Eastern Cordillera or Cordillera Vilcapampa. 
Note the crowded zones on the right (east and north) in contrast to the open sue- 
cession on the left. In sheltered places woodland extends even higher than shown. 
At several points patches of it grow right under the snowline. Other patches grow 
on the floors of the glaciated valley troughs. 

I 

in the marshy spots in the overdeepened parts of the valleys fur- 
nish them with grass for their thatched roofs. And, most im- 



66 THE ANDES OF SOUTHERN PERU 

portant of all, the flat valley floors have the best pasture in the 
whole mountain region. There is plenty of water. There is seclu- 
sion, and, if a fence be built from one valley wall to another as can 
be done with little labor, an entire section of the valley may be 
inclosed. A village like Choquetira, located on a bench on the val- 
ley side, commands an extensive view up and down the valley — an 
important feature in a grazing village where the corrals cannot 
always be built near the houses of the owners. Long, finger-like 
belts of highland-shepherd population have thus been extended 
into the mountain valleys. Sheep and llamas drift right up to 
the snowline. 

There is, however, a marked difference between the people on 
opposite sides of the Cordillera Vilcapampa. On the west the moun- 
tains are bordered by a broad highland devoted to grazing. On 
the east there is a narrower grazing belt leading abruptly down 
to tropical valleys. The eastern or leeward side is also the 
warmer and wetter side of the Cordillera. The snowline is sev- 
eral hundred feet lower on the east. The result is that patches of 
scrub and even a little woodland occur almost at the snowline in 
favored places. Mist and storms are more frequent. The grass 
is longer and fresher. Vegetation in general is more abundant. 
The people make less of wool than of cattle, horses, and mules. 
Vilcabamba pueblo is famous for its horses, wiry, long-haired lit- 
tle beasts, as hardy as Shetland ponies. We found cattle grazing 
only five hundred feet below the limit of perpetual snow. There 
are cultivated spots only a little farther down, and only a thou- 
sand feet below the snow are abandoned terraces. At the same 
elevation are twisted quenigo trees, at least two hundred years 
old, as shown by their rings of growth. Thus the limits of agricul- 
ture are higher on the east; likewise the limits of cattle grazing 
that naturally goes with agriculture. Sheep would thrive, but 
llamas do better in drier country, and the shepherd must needs 
mis his flocks, for the wool which is his chief product requires 
transportation and only the cheap and acclimated llama is at the 
shepherd's disposal. From these facts it will be seen that the 
anthropo-geographic contrasts between the eastern and western 



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Fig. 38. 



Fig. 37 — Cuzco and a portion of the famous Cuzco basin with bordering grassy 
highlands. 

Fig. 38 — Terraced valley slopes and floor, Urubamba Valley between Urubamba 
and Ollantaytambo. 





Fig. 40. 



Fig. 39 — Huieliihua, near Chuquibambilla, a typical mountain village, in tlie 
valleys of the Central Ranges. Peruvian Andes. 

Fig. 40 — Potato field above \'ilcabaniba at 12.000 feet (3.000 m.l. Tlic natural 
sod ia broken by a steel-shod stick and the seed potato dropped into a mere puncture. 
It receives no attention thereafter until harvest time. 



THE COUNTRY OF THE SHEPHERDS 67 

sides of the Cordillera Vilcapampa are as definite as the climatic 
and vegetal contrasts. This is especially well shown in the differ- 
ences between dry Arma, deep-sunk in a glaciated valley west of 
the crest of the mountains, and wet Puquiura, a half -day's journey 
east of the crest. There is no group on the east at all comparable 
to the shepherds of Choquetira, either in the matter of thorough- 
going dependence upon grazing or in that of dependence upon 
glacial topography. 

Topography is not always so intimately related to the life of 
the people as here. In our own country the distribution of avail- 
able water is a far greater factor. The Peruvian Andes therefore 
occupy a distinctive place in geography, since, more nearly than 
in most mountains, their physical conditions have typical human 
relations that enable one clearly to distinguish the limits of con- 
trol of each feature of climate or relief. 



CHAPTEE VI 



THE BORDER VALLEYS OF THE EASTERN ANDES 

On the northeastern border of the Peruvian Andes long moun- 
tain spurs trail down from the regions of snow to the forested 
plains of the Amazon. Here are the greatest contrasts in the 

physical and human geog- 
raphy of the Andean Cordil- 
lera. So striking is the fact 
that every serious student 
of Peru finds himself com- 
pelled to cross and recross 
this natural frontier. The 
thread of an investigation 
runs irregularly now into 
one border zone, now into 
another. Out of the forest 
came the fierce marauders 
who in the early period 
drove back the Inca pioneers. 
Down into the forest to 
escape from the Spaniards 
fled the last Inca and his 
fugitive court. Here the 




FlQ. 41 — Regional diagram of the eastern 
aspect of the Cordillera Vileapampa. See also 
Fig. 17 of which this is an enlarged section. 



Jesuit fathers sowed their 
missions along the forest margin, and watched over them for 
two hundred years. From the mountain border one rubber 
project after another has been launched into the vast swampy 
lowlands threaded by great rivers. As an ethnic boundary 
the eastern mountain border of Peru and Bolivia has no equal 
elsewhere in South America. From the earliest antiquity the 
tribes of the grass-covered mountains and the hordes of the for- 
ested plains have had strongly divergent customs, and speech, that 
bred enduring hatred and led to frequent and bloody strife. 

68 







Fig. 42 — Rug weaver at C'otahuasi. Tlie industry is limited to a small group of 
related families, living in the Cotahuasi Canyon near Cotahuasi. The rugs are made 
of alpaca wool. Pure black, pure white, and various shades of mixed graj' wool are 
employed! The result is that the rugs have " fast " colors that always retain their 
original contrasts. They are made only to order at the homes of the purchasers. The 
money payment is small, bvit to it is added board and lodging, besides tobacco, liqueurs, 
and wine. Before drinking they dip their finger-tips in the wine and sprinkle the 
earth " that it may be fruitful," the air " that it may be warm," the rug " that it may 
turn out well," and finallj' themselves, making the sign of the cross. Then they set 
to work. 




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THE BORDER VALLEYS OF THE EASTERN ANDES 69 

On the steepest spurs of the Pampaconas Valley the traveler 
may go* from snow to pasture in a half day and from pasture to 
forest in the same time. Another day he is in the hot zone of the 
larger valley floors, the home of the Machigangas. The steep 
descents bring out the superimposed zones with diagrammatic 
simplicity. The timber line is as sharply marked as the edge of a 
cultivated field. At a point just beyond the huts of Pampaconas 
one may stand on a grassy spur that leads directly up — a day's 
journey — to the white summits of the Cordillera Vilcapampa. 
Yet so near him is the edge of the forest that he is tempted to 
try to throw a stone into it. In an hour a bitter wind from the 
mountains may drive him to shelter or a cold fog come rolling up 
from the moist region below. It is hard to believe that oppressive 
heat is felt in the valley just beneath him. 

In the larger valleys the geographic contrasts are less sharp 
and the transition from mountains to plain, though less spectacu- 
lar, is much more complex and scientifically interesting. The for- 
est types interfinger along the shady and the sunny slopes. The 
climate is so varied that the forest takes on a diversified character 
that makes it far more useful to man. The forest Indians and 
the valley planters are in closer association. There are many 
islands and peninsulas of plateau population on the valley floor. 
Here the zones of climate and the belts of fertile soil have larger 
areas and the land therefore has greater economic value. Much 
as the valley people need easier and cheaper communication with 
the rest of Peru it is no exaggeration to say that the valley prod- 
ucts are needed far more by the coast and plateau peoples to 
make the republic self-supporting. Coca, wood, sugar, fruit, are 
in such demand that their laborious and costly transportation 
from the valleys to the plateau is now carried on with at least 
some profit to the valley people. Improved transportation would 
promote travel and friendship and supply a basis for greater 
political unity. 

A change in these conditions is imminent. Tears ago the 
Peruvian government decreed the construction of a railway from 
Cuzco to Santa Ana and preliminary surveys were made but -^dth- 



70 THE ANDES OF SOUTHERN PERU 

out any immediate practical effect. By June, 1914, 12.4 miles (20 
km.) had been opened to traffic. The total length of the proposed 
line is 112 miles (180 km.), the gauge is to be only 2.46 feet 
(75 cm.),' and the proposed cost several millions of dollars. The 
financial problem may be solved either by a diversion of local 
revenues, derived from taxes on coca and alcohol, or by borrowed 
foreign capital guaranteed by local revenues. 

A shrubby vegetation is scattered along the valley from the 
village of Urubamba, 12,000 feet (3,658 m.) above sea level, to the 
Canyon of Torontoy. It is local and of little value. Trees appear 
at Ollautaytambo, 11,000 feet (3,353 m.), and here too are more 
extensive wheat and maize fields besides throngs of cacti and 
great patches of wild geraniums. On our valley journey Ave 
camped in pleasant fields flanked by steep hills Avhose summits 
each morning were tipped with snow. Enormous alluvial fans 
have partly filled up the valleys and furnished broad tracts of 
fertile soil. The patient farmers have cleared aAvay the stones on 
the flatter portions and built retaining walls for the smooth fields 
required for irrigation. In places the lower valley slopes are ter- 
raced in the most regular manner (Fig. 38). Some of the fans are 
too steep and stony for cultivation, exposing bare tracts which 
wash doAvn and cover the fields. Here and there are stone walls 
built especially to retain the rush of mud and stones that the rains 
bring down. Many of them were overthroAvn or completely 
buried. Unless the stream channels on the fans are carefully 
watched and effective works kept up, the labor of years may be 
destroyed in a single slide from the head of a steep fan. 

Each group of fans has a population proportioned to its size 
and fertility. If there are broad expanses a town like Urubamba 
or a great hacienda like Huadquiiia is sure to be found. One 
group of huge stony fans below Urubamba (Fig. 180) has only 
a thin population, for the soil is coarse and infertile and the rivers 
deeply intrenched. In some places the tiny fans perched high 
upon the flanks of the mountains where little tributaries burst out 

' Daily Cons, and Trade Report, June 10, 1914, No. 135, and Commcree Reports, 
March 20, 1916, No. 66. 



THE BORDER VALLEYS OF THE EASTERN ANDES 71 

of steep ravines are cultivated by distant owners who also till 
parts of tlie larger fans on the main valley floors. Between the 
fans of the valley bottoms and the smooth slopes of the high 
plateaus are the unoccupied lands — the steep canyon walls. Only 
in the most highly favored places where a small bench or a patch 
of alluvium occurs may one find even an isolated dwelling. The 
stair-like trails, in some places cut in solid rock, zigzag up the 
rocky slopes. An ascent of a thousand feet requires about an 
hour's travel with fresh beasts. The valley people are therefore 
walled in. If they travel it is surely not for pleasure. Even busi- 
ness trips are reduced to the smallest number. The prosperity 
and happiness of the valley people are as well known among the 
plateau people as is their remarkable bread. Their climate has a 
combination of winter rain and winter cold with light frosts that 
is as favorable for good wheat as the continuous winter cold and 
snow cover of our northern Middle West. The colder grainfields 
of the plateau are sowed to barley chiefly, though there is also 
produced some wheat. Urubamba wheat and bread are exported 
in relatively large quantities, and the market demands greater 
quantities than the valley can supply. Oregon and Washington 
flour are imported at Cuzco, two days' muleback journey from the 
wheat fields of Urubamba. 

Such are the conditions in the upper Urubamba Valley. The 
lower valley, beginning at Huadquina, is 8,000 feet (2,440 m.) 
above sea level and extends down to the two-thousand-foot con- 
tour at Eosalina and to one thousand feet (305 m.) at Pongo de 
Mainique. The upper and lower sections are only a score of miles 
(30 km.) apart between Huadquina and Torontoy, but there is a 
difference in elevation of three thousand feet (915 m.) at just the 
level where the maximum contrasts are produced. The cold tim- 
ber line is at 10,500 feet (3,200 m.).^' Winter frosts are common 

- Reference to tlie figures in' this chapter will show great variation in the level 
of the timber line depending upon insolation as controlled by slope exposure and 
upon moisture directly as controlled largely by exposure to winds. In some places 
these controls counteract each other; in other places they promote each other's 
effects. The topographic and climatic cross-sections and regional diagrams else- 
where in this book also emphasize the patchiness of much of the woodland and scrub, 
some noteworthy examples occurring in the chapter on the Eastern Andes. Two of 



72 THE ANDES OF SOUTHERN PERU 

at the one place ; they are absent altogether at the other. Torontoy 
produces corn; Huadquiha produces sugar cane. 

These contrasts are still further emphasized by the sharp topo- 
graphic break between the two unlike portions of the valleJ^ A 
few miles below Torontoy the Urubamba plunges into a mile-deep 
granite canyon. The walls are so close together that it is impos- 
sible from the canyon floor to get into one photograph the highest 
and steepest walls. At one place there is over a mile of descent 
in a horizontal distance of 2,000 feet. Huge granite slabs fall off 
along joint planes inclined but 15° from the vertical. The effect 
is stupendous. The canyon floor is littered with coarse waste and 
the gradient of the river greatly steepened. There is no cultiva- 
tion. The trees cling with difficulty to patches of rock waste or 
to the less-inclined slopes. There is a thin crevice vegetation that 
outlines the joint pattern where seepage supplies the venturesome 
roots with moisture. Man has no foothold here, save at the top 
of the country, as at Machu Picchu, a typical fortress location 
safeguarded by the virtually inaccessible canyon wall and con- 
nected with the main ridge slopes only by an easily guarded 
narrow spur. Toward the lower end of the canyon a little 
finer alluvium appears and settlement begins. Finally, after 
a tumble of three thousand feet over countless rapids the river 
emerges at Colpani, where an enormous mass of alluvium has 
been dumped. The well-intrenched river has already cut a 
large part of it away. A little farther on is Huadquiila in 
the Salcantay Valley, where a tributary of the Urubamba has 
built up a sheet of alluvial land, bright green with cane. From 
the distant peaks of Salcantay and its neighbors Avell-fed streams 
descend to fill the irrigation channels. Thus the snow and rock- 
waste of the distant mountains are turned into corn and sugar on 
the valley lowlands. 

the most remarkable cases are the patch of woodland at 14,500 feet (4,420 m.) just 
under the hanging glacier of Soiroccocha and the other the quenigo scrub on the 
lava plateau above Chuquibamba at 13,000 feet (3,960 m.). The strong compression 
of climatic zones in' the Urubamba Valley below Santa Ana brings into sharp contrast 
the grassy ridge slopes facing the sun and the forested slopes that have a high propor- 
tion of shade. Fig. 54 represents the general .distribution but the details are far 
more complicated. See also Figs. 53 A and 53B. (See Coropuna Quadrangle.) 





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Fig. 44 — The snow-capped Cordillera Vilcapampa north of Yucay and the upper 
canyon of the Urubamba from the wheat fields near Chinehero. In the foreground 
is one of the well-graded mature slopes of Fig. 123. The crests of the mountains lie 
along the axis of a granite intrusion. The extent of the snowfields is extraordinary 
in view of the low latitude, 13° S. 

Fig. 45 — Rounded slopes due to glacial action at Panipaconas in the Pampaconaa 
Valley near Vilcabamba. A heavy tropical forest extends up the Panipaconas Valley 
to the hill slopes in the background. Its upper limit of growth is about 10,000 feet 
(3,050 m.). The camera is pointed slightly downhill. 





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THE BORDER VALLEYS OF THE EASTERN ANDES 73 

The Cordillera Vilcapampa is a climatic as well as a topo- 
grapMc barrier. The southwestern aspect is dry; the northeast- 
ern aspect forested. The gap of the canyon, it should be noticed, 
comes at a ciitical level, for it falls just above the upper border 
of the zone of maximum precipitation. The result is that though 
mists are driven thf-ough the canyon by prolonged up-valley 
winds, they scatter on reaching the plateau or gather high up on 
the flanks of the valley or around the snowy peaks overlooking 
the trail between OUantaytambo and Urubamba. The canyon 
walls are drenched with rains and even some of the lofty spurs 
are clothed with dense forest or scrub. 

Farther down the valley winds about irregularly, now pushed 
to one side by a huge alluvial fan, now turned by some resistant 
spur of rock. Between the front range of the Andes and the 
Cordillera Vilcapampa there is a broad stretch of mountain coun- 
try in the lee of the front range which rises to 7,000 feet (2,134 m.) 
at Abra Tocate (Fig. 15), and falls off to low hills about Eosalina. 
It is all very rough in that there are nowhere any flats except for 
the narrow playa strips along the streams. The dense forest adds 
to the difficulty of movement. In general appearance it is very 
much like the rugged Cascade country of Oregon except that the 
Peruvian forest is' much more patchy and its trees are in many 
places loaded with dense dripping moss which gives the landscape 
a somber touch quite absent from most of the forests of the 
temperate zone. 

The fertility of the eastern valleys of Peru — the result of a 
union of favorable climate and alluvial soil — has drawn the 
planter into this remote section of the country, but how can he dis- 
pose of his products? Even today with a railway to Cuzco from 
the coast it is almost impossible for him to get his sugar and cacao 
to the outside world.^ How did he manage before even this rail- 
way was built? How could the eastern valley planter live before 
there were any railways at all in Peru? In part he has solved 
the problem as the moonshiner of Kentucky tried to solve it, and 

* Commenting on the excellence of the cacao of th'e montana of the Urubamba 
von Tsehudi remarked (op. clt., p. 37) that the long land transport prevented its use 
in Lima where the product on the market is that imported from Guayaquil. 



74 THE ANDES OF SOUTHERN PERU 

from cane juice makes aguardiente (brandy). The latter is a 
much more valuable product than sugar, hence (1) it will bear a 
higher rate of transportation, or (2) it will at the same rate of 
transportation yield a greater net profit. In a remote valley 
where sugar could not be exported on account of high freight 
rates brandy could still be profitably exported. 

The same may be said for coca and cacao. They are condensed 
and valuable products. Both require more labor than sugar but 
are lighter in bulk and thus have to bear, in proportion to their 
value, a smaller share of the cost of transportation. At the end 
of three years coca produces over a ton of leaves per acre per 
year, and it can be made to produce as much as two tons to the 
acre. The leaves are picked four tinies a year. They are worth 
from eight to twelve cents gold a pound at the plantation or six- 
teen cents a pound at Cuzco. An orchard of well-cultivated and 
irrigated cacao trees will do even better. Once they begin to bear 
the trees require relatively little care except in keeping out weeds 
and brush and maintaining the water ditches. However, the pods 
must be gathered at just the right time, the seeds must be raked 
and dried with expert care, and after that comes the arduous 
labor of the grinding. This is done by hand on an inclined plane 
with a heavy round stone whose corners fit the hand. The choco- 
late must then be worked into cakes and dried, or it must be 
sacked in heavy cowhide and sewed so as to be practically air 
tight. When eight or ten years old the trees are mature and each 
may then bear a thousand pounds of seed. 

If labor were cheap and abundant the whole trend of tropical 
agriculture in the eastern valleys would be toward intensive culti- 
vation and the production of expensive exports. But labor is ac- 
tually scarce. Every planter must have agents who can send men 
down from the plateau towns. And the planter himself must use 
his labor to the best advantage. Aguardiente requires less labor 
than cacao and coca. The cane costs about as much in labor the 
first year as the coca bush or the cacao tree, but after that much 
less. The manufacture of brandy from the cane juice requires lit- 
tle labor though much expensive machinery. For chocolate, a 




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THE BORDER VALLEYS OF THE EASTERN ANDES 75 

storehouse, a grinding stone, and a rake are all tliat are required. 
So the planter must work out his own salvation individually. He 
must take account of the return upon investments in machinery, 
of the number of hands he can command from among the "faena" 
or free Indians, of the cost and number of imported hands from 
the valley and plateau towns, and, finally, of the transportation 
rates dependent upon the number of mules in the neighborhood, 
and distance from the market. If in addition the labor is skilfully 
employed so as to have the tasks which the various products re- 
quire fall at different periods of the year, then the planter may 
expect to make money upon his time and get a return upon his 
initial investment in the land.* 

The type of tropical agriculture which we have outlined is 
profitable for the few planters who make up the white population 
of the valleys, but it has a deplorable effect upon the Indian popu- 
lation. Though the planters, one and all, complain bitterly of the 
drunken habits of their laborers, they themselves put into the 
hands of the Indians the means of debauchery. Practically the 
whole production of the eastern valleys is consumed in Peru. 
What the valleys do not take is sent to the plateau, where it is the 
chief cause of vicious conduct. Two-thirds of the prisoners in the 
city jails are drunkards, and, to be quite plain, they are virtually 
supplied with brandy by the planter, who could not otherwise 
make enough money. So although the planter wants more and 
better labor he is destroying the quality of the little there is, and, 
if not actually reducing the quantity of it, he is at least very cer- 
tainly reducing the rate of increase. 

The difficulties of the valley planter could be at least partly 
overcome in several ways. The railway will reduce transporta- 
tion costs, especially when the playas of the valleys are all 
cleared and the exports increased. Moreover the eastern valleys 

* The inadequacy of the labor supply was a serious obstacle in the early days 
as well as now. In the documents pertaining to the " Obispados y Audiencia del 
Cuzco" (Vol. 11, p. 349 of the " Juicio de Ltoites entre el Peril y Bolivia, Prueba 
Peruana presentada al Gobierno de la ReptJblica Argentina por Victor M. Maurtua," 
Barcelona, 1906) we find the report that the natives of the curacy of Ollantaytambo 
who came down from the hills to Huadquifia to hear mass were detained and compelled 
to give a day's service on the valley plantations under pain of chastisement. 



76 THE ANDES OF SOUTHERN PERU 

are capable of producing things of greater utility than brandy 
and coca leaves. So far as profits are increased by cheaper trans- 
portation we may expect the planter to produce more rather than 
less of brandy and coca, his two most profitable exports, unless 
other products can be found that are still more profitable. The 
ratio of profits on sugar and brandy will still be the same unless 
the government increases the tax on brandy until it becomes no 
more profitable than sugar. That is what ought to be done for 
the good of the Indian population. It cannot be done safely with- 
out offering in its place the boon of cheaper railway transporta- 
tion for the sugar crop. Furthermore, with railway improve- 
ments should go the blessings that agricultural experiments can 
bestow. A government farm in a suitable place would establish 
rice and cotton cultivation. Many of the playas or lower alluvial 
lands along the rivers can be irrigated. Only a small fraction of 
the water of the Rio Urubamba is now turned out upon the fields. 
For a large part of the year the natural rainfall would suffice to 
keep rice in good condition. Six tons a year are now grown on 
Hacienda Sahuayaco for local use on account of the heavy rate 
on rice imported on mnleback from Cuzco, whither it comes by 
sea and by trail from distant coastal valleys. The lowland people 
also need rice and it could be sent to them down river by an easier 
route than that over which their supplies now come. It should be 
exported to the highlands, not imported therefrom. There are so 
many varieties adapted to so many kinds of soil and climate that 
large amounts should be produced at fair profits. 

The cotton plant, on the other hand, is more particular about 
climate and especially the duration of dry and wet seasons; in 
spite of this its requirements are all met in the Santa Ana Valley. 
The rainfall is moderate and there is an abundance of dry warm 
soil. The plant could make most of its growth in the wet season, 
and the four months of cooler dry season wath only occasional 
showers would favor both a bright staple and a good picking sea- 
son. More labor would be required for cotton and rice and for 
the increased production of cacao than under the present system. 
This would not be a real difficulty if the existing labor supply 



THE BORDER VALLEYS OF THE EASTERN ANDES 77 

were conserved by the practical abolition, through heavy taxation, 
of the brandy that is the chief cause of the laborer's vicious habits. 
This is the first step in securing the best return upon the capital 
invested in a railway. Economic progress is here bound up with 
a very practical morality. Colonization in the eastern valleys, of 
which there have been but a few dismal attempts, will only extend 
the field of influence, it will not solve the real problem of bringing 
the people of the rich eastern territory of Peru into full and 
honorable possession of their natural wealth. 

The value of the eastern valleys was known in Inca times, for 
their stone-faced terraces and coca-drying patios may still be seen 
at Echarati and on the border of the Chaupimayu Valley at 
Sahuayaco. Tradition has it that here were the imperial coca 
lands, that such of the forest Indians as were enslaved were 
obliged to work upon them, and that the leaves were sent to Cuzco 
over a paved road now covered with "montaiia" or forest. The 
Indians still relate that at times a mysterious, wavering, white 
light appears on the terraces and hills where old treasure lies 
buried. Some of the Indians have gold and silver objects which 
they say were dug from the floors of hill caves. There appears to 
have been an early occupation of the best lands by the Spaniards, 
for the long extensions down them of Quechua population upon 
which the conquerors could depend no doubt combined with the 
special products of the valley to draw white colonists thither." 

' The Spanish occupation of the eastern valleys was early and extensive. Im- 
mediately after the capture of the young Inca Tupac Amaru and the final subjugation 
of the province of Vilcapampa colonists started the cultivation of coca and cane. 
Development of the main Urubamba Valley and tributary valleys proceeded at a good 
rate: so also did their troubles. Baltasar de Ocampo writing in 1610 (Account of the 
Province of Vilcapampa, Hakluyt Soc. Pubis., Ser. 2, Vol. 22, 1907, pp. 203-247) relates 
the occurrence of a general uprising of the negroes employed on the sugar plantations 
of the region. But the peace and prosperity of every place on the eastern frontier was 
unstable and quite generally the later eighteenth and earlier nineteenth centuries saw 
a retreat of the border of civilization. The native rebellion of the mid-eighteenth 
century in the montana of Chanchamayo caused entire abandonment of a previously 
flourishing area. When Eaimondi wrote in 1885 (La Montana de Chanchamayo, Lima, 
1885 ) some of the ancient hacienda sites were still occupied by savages. In the 
Paucartambo valleys, settlement began by the end of the sixteenth century and at the 
beginning of the nineteenth before their complete desolation by the savages they were 
highly prosperous. Paucartambo town, itself, once important for its commerce in coca 
is now in a sadly decadent condition. 



78 THE ANDES OF SOUTHERN PERU 

General Miller," writing in 1836, mentions the villages of Incharate 
(Echarati) and Sant' Ana (Santa Ana) but discourages the 
idea of colonization "... since the river . . . has lofty moun- 
tains on either side of it, and is not navigable even for boats." 

In the "Itinerario de los viajes de Eaimondi en el Peru" ' there 
is an interesting account of the settlement by the Eueda family 
of the great estate still held by a Eueda, the wife of Sefior Duque. 
Jose Eueda, in 1829, was a government deputy representative and 
took his pay in land, acquiring valuable territory on which there 
was nothing more than a mission. In 1830 Eueda ceded certain 
lands in "arriendo" (rent) and on these Avere founded the haci- 
endas Pucamoco, Sahuayaco, etc. 

Seiior Gonzales, the present owner of Hacienda Sahuayaco, re- 
cently obtained his land — a princely estate, ten miles by forty — 
for 12,000 soles ($6,000). In a few years he has cleared the best 
tract, built several miles of canals, hewed out houses and furni- 
ture, planted coca, cacao, cane, coffee, rice, pepper, and cotton, 
and would not sell for $50,000. Moreover, instead of being a 
superintendent on a neighboring estate and keeping a shop 
in Cuzco, where his large family was a source of great ex- 
pense, he has become a wealthy landowner. He has educated a 
son in the United States. He is importing machinery, such as a 
rice thresher and a distilling plant. His son is looking forward 
to the purchase of still more playa land down river. He pays a 
sol a day to each laborer, securing men from Cotabambas and 
Abancay, where there are many Indians, a low standard of wages, 
little unoccupied land, and a hot climate, so that the immigrants 
do not need to become acclimatized. 

The deepest valleys in the Eastern Andes of Peru have a 
semi-arid climate which brings in its train a variety of unusual 
geographic relations. At first as one descends the valley the 
shady and sunny slopes show sharply contrasted vegetation. 



' Notice of a Journey to the Northward and also to the Eastward of Cuzco, and 
among the Chunchoa Indians, in July, 1835. Journ. Royal Geog. Soc, Vol. fi, 1836, 
pp. 174-186. 

' Bol. Soc. Geog. de Lima, Vol. 8, 1898, p. 45. 




Fig. 51. 




Fig. 52. 



Fig. 51 — Eobledo's mountain-side trail in the Urubamba Valley below Rosalina. 

Fig. 52 — An epiphyte partly supported by a dead host at Rosalina, elevation 2,000 
feet. The epiphyte bears a striking resemblance to a horned beast whose arched back, 
tightly clasped fingers, and small eyes give it a peculiarlj' malignant and life-like 
expression. 




Fig. 53A. 




Fig. 33B. 



Fig. 53A — The smooth grassy slopes at the junction of the Yanatili (left) and 
Uruhamba (right) rivers near Pabellon. 

Fig. o3B — Distribution of vegetation in the Urubamba Valley near Torontoy. The 
patches of timber in the backgi'ound occupy the shady sides of the spurs; the sunny 
slopes are grass-covered; the valley floor is filled with thickets and patches of wood- 
land but not true forest. 



THE BORDER VALLEYS OF THE EASTERN ANDES 79 



The one is forested, the other grass-cov- 
ered. Slopes that receive the noon and 
afternoon sun the greater part of the year 
are hottest and therefore driest. For 
places in 11° south latitude the sun is well 
to the north six months of the year, nearly 
overhead for about two months, and to the 
south four months. Northwesterly as- 
pects are therefore driest and warmest, 
hence also grass-covered. In many places 
the line between grass and forest is de- 
veloped so sharply that it seems to be the 
artificial edge of a cut-over tract. This is 
true especially if the relief is steep and 
the hill or ridge-crests sharp.' 

At Santa Ana this feature is developed 
in an amazingly clear manner, and it is 
also combined with the dry timber line and 
with producti\-ity in a way I have never 
seen equaled elsewhere. The diagram will 
explain the relation. It will be seen that 
the front range of the mountains is high 
enough to shut off a great deal of rainfall. 
The lower hills and ridges just within the 
front range are relatively dry. The deep 
valleys are much drier. Each broad ex- 
pansion of a deep valley is therefore a dry 
pocket. Into it the sun pours even when 

' Ma-rcoy who traveled in Peru in the middle of the 
last century was greatly impressed by the sympathetic 
changes of aspect and topography and vegetation in the 
eastern valleys. He thus describes a sudden change of 
scene in the Occobamba valley: "... the trees had dis- 
appeared, the birds had taken wing, and great sandy 
spaces, covered with the latest deposits of the river, al- 
ternated with stretches of yellow grass and masses of 
rock half -buried in the ground." (Travels in South 
America, translated by Elihu Rich, 2 vols. New York, 
1875, Vol. 1, p. 326.) 



< I 




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[=. 



80 THE ANDES OF SOUTHERN PERU 

all the surrounding hills and mountains are "^Tapped in cloud. 
The greater number of hours of sunshine hastens the rate of 
evaporation and still further increases the dryness. Under the 
spur of much sunlight and of ample irrigation water from the 
wetter hill slopes, the dry valley pockets produce huge crops of 
fruit and cane. 

The influence of the local climate upon tree growth is striking. 
Every few days, even in the relatively dry winter season, clouds 
gather about the hills and there are local showers. The lower 
limit of the zone of clouds is sharply marked and at both Santa 
Ana and Echarati it is strikingly constant in elevation — about 
five thousand feet above sea level. From the upper mountains 
the forest descends, with only small patches of glade and prairie. 
At the lower edge of the zone of cloud it stops abruptly on the 
warmer and drier slopes that face the afternoon sun and continues 
on the moister slopes that face the forenoon sun or that slope 
away from the sun. 

But this is not the only response the vegetation makes. The 
forest changes in character as well as in distribution. The forest 
in the wet zone is dense and the undergrowth luxuriant. In the 
selective slope forest below the zone of cloud the undergrowth is 
commonly thin or wanting and the trees grow in rather even-aged 
stands and by species. Finally, on the valley floor and the tribu- 
tary fans, there is a distinct growth of scrub with bands of trees 
along the water courses. Local tracts of coarse soil, or less rain 
on account of a deep "hole" in a valley surrounded by steeper 
and higher mountains, or a change in the valley trend that brings 
it into less free communication with the prevailing winds, may 
still further increase the dryness and bring in a true xerophytic 
or drought-resisting vegetation. Cacti are common all through 
the Santa Ana Valley and below Sahuayaco there is a patch of 
tree cacti and similar forms several square miles in extent. Still 
farther do^vn and about half-way between Sahuayaco and Pabel- 
lon are immense tracts of grass-covered mountain slopes (Fig. 
53). These extend beyond Eosalina, the last of them terminating 
near Abra Tocate (Fig. 15). The sudden interruption is due to a 



THE BORDER VALLEYS OF THE EASTERN ANDES 81 



icharaii 

3C*Ltor Mrits 



turn in the valley giving freer access to the up-valley winds that 
sweep through the pass at Pongo de Mainique. 

Northward from Abra Tocate (Fig. 55) the forest is prac- 
tically continuous. The break between the two vegetal regions 
is emphasized by a corral for cattle and mules, the last 
outpost of the plateau 
herdsmen. Not three 
miles away, on the oppo- 
site forested slope of the 
valley, is the first of the 
Indian clearings where 
several families of Machi- 
gangas spend the wet sea- 
son when the lower river 
is in flood (Fig. 21). The 
grass lands will not yield 
corn and coca because the 
soil is too thin, infertile, 
and dry. The Indian 
farms are therefore all in 
the forest and begin al- 
most at its very edge. 
Here finally terminates a 
long peninsula of grass- 
covered country. Below this point the heat and humidity rapidly 
increase; the rains are heavier and more frequent; the country 
becomes almost uninliabitable for stock; transportation rates 
double. Here is the undisputed realm of the forest with new kinds 
of trees and products and a distinctive type of forest-dwelling 
Indian. 

At the next low pass is the skull of an Italian who had mur- 
dered his companions and stolen a season's picking of rubber, at- 
tempting to escape by canoe to the lower Urubamba from the 
Pongo de Mainique. The Machigangas overtook him in their 
swiftest dugouts, spent a night with him, and the next morning 
shot him in the back and returned with their rightful property — 




FiQ. 55 — Map to show the relation of the 
grasslands of the dry lower portion of the 
Urubamba Valley (unshaded) to the forested 
lands at higher elevations (shaded). See Fig. 
54 for climatic conditions. Patches and slender 
tongues of woodland occur below the main 
timber line and patches of grassland above it. 



82 THE ANDES OF SOUTHERN PERU 

a harvest of rubber. For more than a decade foreigners have been 
coming down from the plateau to exploit them. They are an inde- 
pendent and free tribe and have simple yet correct ideas of right 
and wrong. Their chief, a man of great strength of character 
and one of the most likeable men I have known, told me that he 
placed the skull in the pass to warn away the whites who came to 
rob honest Indians. 

The Santa Ana Valley between the Canyon of Torontoy and 
the heavy forest belt below Eosalina is typical of many of the 
eastern valleys of Peru, both in its physical setting and in its 
economic and labor systems. Westward are the outliers of the 
Vilcapampa range; on the east are the smaller ranges that front 
the tropical lowlands. Steep valleys descend from the higher 
country to join the main valley and at the mouth of every tribu- 
tary is an alluvial fan. If the alluvium is coarse and steeply in- 
clined there is only pasture on it or a growth of scrub. If fine and 
broad it is cleared and tilled. The sugar plantations begin at 
Huadquina and end at Eosalina. Those of Santa Ana and 
Echarati are the most productive. It takes eighteen months for 
the cane to mature in the cooler weather at Huadquina (8,000 feet). 
Less than a year is required at Santa Ana (3,400 feet). Patches 
of alluvium or playas, as they are locally called, continue as far 
as Santo Anato, but they are cultivated only as far as Eosalina. 
The last large plantation is Pabellon ; the largest of all is Echarati. 
All are irrigated. In the wet months, December to March inclu- 
sive, there is little or no irrigation. In the four months of the dry 
season, June to September inclusive, there is frequent irrigation. 
Since the cane matures in about ten months the harvest seasons 
fall irregularly with respect to the seasons of rain. Therefore the 
land is cleared and planted at irregular intervals and labor dis- 
tributed somewhat through the year. There is however a concen- 
tration of labor toward the end of the dry season when most of 
the cane is cut for grinding. 

The combined freight rate and government tax on coca, sugar, 
and brandy take a large part of all that the planter can get for 
his crop. It is 120 miles (190 km.) from Santa Ana to Cuzco and 



THE BORDER VALLEYS OF THE EASTERN ANDES 83 

it takes five days to make the journey. The freight rate on coca 
and sugar for mule carriage, the only kind to be had, is two cents 
per pound. The national tax is one cent per pound (0.45 kg.). 
The coca sells for twenty cents a pound. The cost of production 
is unknown, but the paid labor takes probably one-half this 
amount. The planter's time, capital, and profit must come out 
of the rest. On brandy there is a national tax of seven cents per 
liter (0.26 gallon) and a municipal tax of two and a half cents. 
It costs five cents a liter for transport to Cuzco. The total in 
taxes and transport is fourteen and a half cents a liter. It sells 
for twenty cents a liter. Since brandy (aguardiente), cacao (for 
chocolate), and coca leaves (for cocaine) are the only precious sub- 
stances which the valleys produce it takes but a moment's inspec- 
tion to see how onerous these taxes would be to the planter if 
labor did not, as usual, pay the penalty. 

Much of the labor on the plantations is free of cost to the 
owner and is done by the so-called faena or free Indians. These 
are Quechuas who have built their cabins on the hill lands 
of the planters, or on the floors of the smaller valleys. The dis- 
position of their fields in relation to the valley plantations is full 
of geographic interest. Each plantation runs at right angles to 
the course of the valley. Hacienda Sahuayaco is ten miles (16 
km.) in extent down valley and forty miles (64 km.) from end to 
end across the valley, and it is one of the smaller plantations ! It 
follows that about ten square miles lie on the valley floor and half 
of this can ultimately be planted. The remaining three hundred 
and ninety square miles include some mountain country with pos- 
sible stores of mineral wealth, and a great deal of "fells" coun- 
try — grassy slopes, graded though steep, excellent for pasture, 
with here and there patches of arable land. But the hill country 
can be cultivated only by the small farmer who supplements his 
supply of food from cultivated plants like potatoes, corn, and 
vegetables, by keeping cattle, mules, pigs, and poultry, and by 
raising coca and fruit. 

The Indian does not own any of the land he tills. He has the 
right merely to live on it and to cultivate it. In return he must 



84 THE ANDES OF SOUTHERN PERU 

work a certain number of days each year on the owner's planta- 
tion. In many cases a small money payment is also made to the 
planter. The planter prefers labor to money, for hands are 
scarce throughout the whole eastern valley region. Xo Indian 
need work on the planter's land mthout receiving pay directly 
therefor. Each also gets a small weekly allotment of aguardiente 
while in the planter's employ. 

The scene every Saturday night outside the office of the con- 
tador (treasurer) of a plantation is a novel one. Several hundred 
Indians gather in the dark patio in front of the office. Within 
the circle of the feeble candlelight that reaches only the margin 
of the crowd one may see a pack of heavy, perspiring faces. Many 
are pock-marked from smallpox ; here and there an eye is missing ; 
only a few are jovial. A name is shouted through the open door 
and an Indian responds. He pulls off his cap and stands stupid 
and blinking, while the contador asks : 

"Faena" (free)? 

"Si, Senor," he answers. 

"Un sol" (one "sol" or fifty cents gold). The assistant hands 
over the money and the man gives way to the next one on the list. 
If he is a laborer in regular and constant employ he receives five 
soles (two fifty gold) per week. There are interruptions now and 
then. A ragged, half-drunken man has been leaning against the 
door post, suspiciously impatient to receive his money. Finally 
his name is called. 

"Faena?" asks the contador. 

"No, Senor, cinco (five) soles." 

At that the field superintendente glances at his time card and 
speaks up in protest. 

"You were the man that failed to show up on Friday and Sat- 
urday. You were drunk. You should receive nothing." 

"No, mi patron," the man contends, "I had to visit a sick 
cousin in the next valley. Oh, he was very sick, Seiior," and he 
coughs harshly as if he too were on the verge of prostration. The 
sick cousin, a faena Indian, has been at work in another cane field 
on the same plantation for two days and now calls out that he is 



THE BORDER VALLEYS OF THE EASTERN ANDES 85 

present and has never had a sick day in his life. Those outside 
laugh uproariously. The contador throws down two soles and 
the drunkard is pushed back into the sweating crowd, jostled 
right and left, and jeered by all his neighbors as he slinks away 
grumbling. 

Another Indian seems strangely shy. He scarcely raises his 
voice above a whisper. He too is a faena Indian. The contador 
finds fault. 

"Why didn't you come last month when I sent for you?" 

The Indian fumbles his cap, shuffles his feet, and changes his 
coca cud from one bulging cheek to the other before he can an- 
swer. Then huskily: 

"I started, Senor, but my woman overtook me an hour after- 
ward and said that one of the ewes had dropped a lamb and 
needed care." 

' ' But your woman could have tended it ! " 

"No, Senor, she is sick." 

"How, then, could she have overtaken you?" he is asked. 

' ' She ran only a little way and then shouted to me. ' ' 

"And what about the rest of the month? ' ' persists the contador. 

"The other lambs came, Senor, and I should have lost them 
all if I had left." 

The contador seems at the end of his complaint. The Indian 
promises to work overtime. His difficulties seem at an end, but 
the superintendent looks at his old record. 

"He always makes the same excuse. Last year he was three 
weeks late." 

So the poor shepherd is fined a sol and admonished that his 
lands will be given to some one else if he does not respond more 
promptly to his patron's call for work. He leaves behind him a 
promise and the rank mixed smell of coca and much unwashed 
woolen clothing. 

It is not alone at the work that they grumble. There is ma- 
laria in the lower valleys. Some of them return to their lofty 
mountain homes prostrated with the unaccustomed heat and alter- 
nately shaking with chills and burning with fever. "Without aid 



86 THE ANDES OF SOUTHERN PERU 

they may die or become so weakened that tuberculosis carries 
them off. Only their rugged strength enables the greater number 
to return in good health. 

A plantation may be as large as a principality and draw its 
laborers from places fifty miles away. Some of the more distant 
Indians need not come to work in the canefields. Part of their 
flock is taken in place of work. Or they raise horses and mules 
and bring in a certain number each year to turn over to the 
patron. Hacienda Huadquiiia (Fig. 46) takes in all the land from 
the snow-covered summits of the Cordillera Vilcapampa to the 
canefields of the Urubamba. Within the broad domain are half 
the climates and occupations characteristic of Peru. It is diffi- 
cult to see how a thousand Indians can be held to even a mixed 
allegiance. It seems impossible that word can be got to them. 
However the native "telegraph" is even more perfect than that 
among the forest Indians. From one to the other runs the news 
that they are needed in the canefields. On the trail to and from 
a mountain village, in their ramblings from one high pasture to 
another, within the dark walls of their stone and mud huts when 
they gather for a feast or to exchange drinks of brandy and 
chicha — the word is passed that has come up from the valleys. 

For every hundred faena Indians there are five or six regular 
laborers on the plantations, so mth the short term passed by the 
faena Indians their number is generally half that of the total 
laborers at work at any one time. They live in huts provided for 
them by the planter, and in the houses of their friends among the 
regTilar laborers. Here there are almost nightly carousals. The 
regular laborer comes from the city or the valley town. The faena 
laborer is a small hill farmer or shepherd. They have much to 
exchange in the way of clothing, food, and news. I have fre- 
quently had their conversations interpreted for me. They ask 
about the flocks and the children, who passed along the trails, what 
accidents befell the people. 

"Last year," droned one to another over their chicha, "last 
year we lost three lambs in a hailstorm up in the high fields near 
the snow. It was very cold. My foot cracked open and, though 



THE BORDER VALLEYS OF THE EASTERN ANDES 87 

I have bound it with wet coca leaves every night, it will not cure, ' ' 
and he displays his heel, the skin of which is like horn for hard- 
ness and covered with a crust of dirt whose layers are a record 
of the weather and of the pools he has waded for years. 

Their wanderings are the main basis of conversation. They 
know the mountains better than the condors do. We hired a small 
boy of twelve at Puquiura. He was to build our fires, carry water, 
and help drive the mules. He crossed the Cordillera Vilcapampa 
on foot with us. He scrambled down into the Apurimac canyon 
and up the ten thousand feet of ascent on the other side, tAvisted 
the tails of the mules, and shouted more vigorously then the ar- 
rieros. He was engaged to go with, us to Pasaje, where his father 
would return with him in a month. But he climbed to Huascatay 
with us and said he wanted to see Abancay. When an Indian 
whom we pressed into service dropped the instruments on the 
trail and fled into the brush the boy packed them like a man. The 
soldier carried a tripod on his back. The boy, not to be outdone, 
insisted on carrying the plane table, and to his delight we called 
him a soldier too. He went with us to Huancarama. When I paid 
him he smiled at the large silver soles that I put into his hand; 
and when I doubled the amount for his Avillingness to work his joy 
was unbounded. Forthwith he set out, this time on muleback, on 
the return journey. The last I saw of him he was holding his 
precious soles in a handkerchief and kicking his beast with his 
bare heels, as light-hearted as a cavalier. Often I find myself won- 
dering whether he returned safely with his money. I should very 
much like to see him again, for with him I associate cheerfulness 
in difficult places and many a pleasant camp-fire. 



CHAPTER VII 

THE GEOGRAPHIC BASIS OF REVOLUTIONS AND OF HUMAN 
CHARACTER IN THE PERUVIAN ANDES 

Human character as a spontaneous development has always 
been a great factor in shaping historical events, but it is a strik- 
ing fact that in the world of our day its influence is exerted chiefly 
in the lowest and highest types of humanity. The savage with 
his fetishes, his taboos, and his inherent childlikeness and suspi- 
cion needs only whim or a slight religious pretext to change his 
conduct. Likewise the really educated and the thoughtful act from 
motives often wholly unrelated to economic conditions or results. 
But the masses are deeply influenced by whatever affects their 
material welfare. A purely idealistic impulse may influence a 
people, but in time its effects are always displayed against an eco- 
nomic background. 

There is a way whereby we may test this theory. In most 
places in the world we have history in the making, and through 
field studies we can get an intimate view of it. It is peculiarly 
the province of geography to study the present distribution 
and character of men in relation to their surroundings and 
these are the facts of mankind that must forever be the chief 
data of economic history. It is not vain repetition to say that this 
means, first of all, the study of the character of men in the fullest 
sense. It means, in the second place, that a large part of the char- 
acter must be really understood. Whenever this is done there is 
found a geographic basis of human character that is capable of the 
clearest demonstration. It is in the geographic environment that 
the material motives of humanity have struck their deepest roots. 

These conclusions might be illustrated from a hundred places 
in the field of study covered in this book. Almost every chapter 
of Part I contains facts of this character. I wish, however, to dis- 
ss 



THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 89 

cuss the subject specifically and for that purpose now turn to the 
conditions of life in the remoter mountain valleys and to one or 
two aspects of the revolutions that occur now and then in Peru. 
The last one terminated only a few months before our arrival and 
it was a comparatively easy matter to study both causes and 
effects. 

A caution is necessary however. It is a pity that we use the 
term "revolution" to designate these little disturbances. They 
affect sometimes a few, again a few hundred men. Barely do 
they involve the whole country. A good many of them are on a 
scale much smaller than our big strikes. Most of them involve 
a loss of life smaller than that which accompanies a city riot. They 
are in a sense strikes against the government, marked by local dis- 
orders and a little violence. 

Early in 1911 the Prefect of the Department of Abancay had 
crowned his long career by suppressing a revolution. He had 
been Subprefect at Andahuaylas, and when the rebels got control 
of the city of Abancay and destroyed some of the bridges on the 
principal trails, he promptly organized a military expedition, con- 
structed rafts, floated his small force of men across the streams, 
and besieged the city. The rebel force was driven at last to take 
shelter in the city jail opposite the Prefectura. There, after the 
loss of half their number, they finally surrendered. Seventy-five 
of them were sent to the government penitentiary at Arequipa. 
Among the killed were sons from nearly half the best families of 
Abancay. All of the rebels were young men. 

It would be difficult to give an adequate idea of the hatred felt 
by the townspeople toward the government. Every precaution 
was taken to prevent a renewal of the outbreak. Our coming was 
telegraphed ahead by government agents who looked with suspi- 
cion upon a party of men, well armed and provisioned, coming up 
from the Pasaje crossing of the Apurimac, three days' journey 
north. The deep canyon affords shelter not only to game, but also 
to fugitives, rebels, and bandits. The government generally 
abandons pursuit on the upper edge of the canyon, for only a pro- 
longed guerilla warfare could completely subdue an armed force 



90 THE ANDES OF SOUTHERN PERU 

scattered aloug its rugged walls and narrow floor. The owner of 
tlie hacienda at Pasaje is required to keep a record of all passen- 
gers rafted across the Apurimac, but he explains significantly that 
some who pass are too hurried to write their names in his book. 
Once he reaches the eastern wall of the canyon a fugitive may 
command a view of the entire western wall and note the api^roach 
of pursuers. Thence eastward he has the Avhole Cordillera \'ilca- 
pampa in which to hide. Pursuit is out of the question. 

When we arrived, the venerable Prefect, a model of old-fash- 
ioned courtesy, greeted us with the utmost cordiality. He told us 
of our movements since leaving Pasaje, and laughingly explained 
that since we had sent him no friendly message and had come 
from a rebel retreat, he had taken it for granted that we intended 
to storm the town. I assured him that we were ready to join his 
troops, if necessary, whereupon, with a delightful frankness, he 
explained his method of keeping the situation in hand. Several 
troops of cavalry and two battalions of infantry were quartered 
at the government barracks. Every evening the old gentleman, 
a Colonel in the Peruvian army, mounted a powerful gray horse 
and rode, quite unattended, through the principal streets of the 
town. Several times I walked on foot behind him, again I pre- 
ceded him, stopping in shops on the way to make trivial purchases, 
to find out what the people had to say about him and the govern- 
ment as he rode by. One old gentleman interested me particularly. 
He had only the day before called at the Prefectura to pay his 
respects. Although his manner was correct there was lacking to 
a noticeable degree the profusion of sentiment that is apt to be 
exhibited on such an occasion. He now sat on a bench in a shop. 
Both his own son and the shopkeeper's son had been slain in the 
revolution. It was natural that they should be bitter. But the 
precise nature of their complaint was what interested me most. 
One said that he did not object to having his son lose his life for 
his country. But that his country's officials should hire Indians 
to shoot his son seemed to him sheer murder. Later, at Lam- 
brama, I talked with a rebel fugitive, and that was also his com- 
plaint. The young men drafted into the army are Indians, or 




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Fig. 59. 



Fig. 58 — Crossing the Apurimac at Pasaje. These are mountain liorses, small and 
wiry, with a protective coat of long hair. They are accustomed to graze in the open 
without shelter during the entire winter. 

Fig. 59 — Crossing the Apurimac at Pasaje. The mules are blindfolded and pushed 
off the steep bank into the water and rafted across. 



THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 91 

mixed, never whites. White men, and men with a small amount 
of Indian blood, officer the army. When a revolutionary party 
organizes it is of course made up wholly of men of white and 
mixed blood, never Indians. The Indians have no more grievance 
against one white party than another. Both exploit him to the 
limit of law and beyond the limit of decency. He fights if he must, 
but never by choice. 

Thus Indian troops killed the white rebels of Abancay. 

"Tell me, Senor," said the fugitive, "if you think that just. 
Tell me how many Indians you think a white man worth. Would 
a hundred dead Indians matter? But how replace a white man 
where there are so few? The government assassinated my com- 
patriots ! ' ' 

"But," I replied, "why did you fight the government? All of 
you were prosperous. Your fathers may have had a grievance 
against the government, but of what had you young men to com- 
plain?" 

His reply was far from convincing. He Avas at first serious, but 
his long abstract statements about taxes and government waste- 
fulness trailed off into vagueness, and he ended in a laughing 
mood, talking about adventure, the restless spirit of young men, 
and the rich booty of confiscated lands and property had the 
rebels won. He admitted that it was a reckless game, but when I 
called him a mere soldier of fortune he grew serious once more 
and reverted to the iniquitous taxation system of Peru. Further 
inquiry made it quite clear that the ill-fated revolution of Abancay 
was largely the work of idle young men looking for adventure. 
It seemed a pity that their splendid physical energy could not 
have been turned into useful channels. The land sorely needs en- 
gineers, progressive ranchmen and farmers, upright officials, and 
a spirit of respect for law and order. Old men talked of the un- 
stable character of the young men of the time, but almost all of 
them had themselves been active participants in more than one 
revolution of earlier years. 

Every night at dinner the Prefect sent off by government tele- 
graph a long message to the President of the Eepublic on the 



92 THE ANDES OF SOUTHERN PERU 

state of the Department, and received similar messages from the 
central government about neighboring departments. These he 
read to us, and, curiously enough, to the entire party, made up 
of army officers and townsmen. I was surprised to find later that 
the company included one govex-nment official whose son had been 
among the imprisoned rebels at Arequipa. We met the young 
man a week later at a mountain village, a day after a general 
amnesty had been declared. His escape had been made from the 
prison a month before. He forcibly substituted the mess-boy's 
clothing for his own, and thus passed out unnoticed. After a few 
days' hiding in the city, he set out alone across the desert of Vitor, 
thence across the lofty volcanic country of the Maritime Andes, 
through some of the most deserted, inhospitable land in Peru, and 
at the end of three weeks had reached Lambrama, near Abancay, 
the picture of health ! 

Later I came to have a better notion of the economic basis of 
the revolution, for obviously the planters and the reckless young 
men must have had a mutual understanding. Somewhere the 
rebels had obtained the sinews of war. The planters did not take 
an open part in the revolution, but they financed it. When the 
rebels were crushed, the planters, at least outwardly, welcomed 
the government forces. Inwardly they cursed them for thwart- 
ing their scheme. The reasons have an interesting geographic 
basis. Abancay is the center of a sugar region. Great irrigated 
estates are spread out along the valley floor and the enormous al- 
luvial fans built into the main valley at the mouths of the tribu- 
tary streams. There is a heavy tax on sugar and on aguardiente 
(brandy) manufactured from cane juice. The hacendados had 
dreamed of lighter taxes. The rebels otfered the means of secur- 
ing relief. But taxes were not the real reason for the unrest, for 
many other sugar producers pay the tax without serious com- 
plaint. Abancay is cut off from the rest of Peru by great moun- 
tains. Toward the west, via Antabamba, Cotahuasi, and Chuqui- 
bamba, two hundred miles of trail separate its plantations from 
the Pacific. Twelve days' hard riding is required to reach Lima 
over the old colonial trade route. It is three davs to Cuzco at the 



THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 93 

end of the three-hundred-mile railway from the port of MoUendo. 
The trails to the Atlantic rivers are impossible for trading pur- 
poses. Deep sunk in a subtropical valley, the irrigable alluvial 
land of Abancay tempts the production of sugar. 

But nature offers no easy route out of the valley. For cen- 
turies the product has been exported at almost prohibitive cost, 
as in the eastern valley of Santa Ana. The coastal valleys 
enjoy easy access to the sea. Each has its own port at the 
valley mouth, where ocean steamers call for cargo. Many have 
short railway lines from port to valley head. The eastern 
valleys and Abancay have been clamoring for railways, better 
trails, and wagon roads. From the public fund they get what 
is left. The realization of their hopes has been delayed too 
long. It would be both economic and military strategy to give 
them the desired railway. Kevolutions in Peru always start 
in one of two ways : either by a coup at Lima or an unchecked 
uprising in an interior province. Bolivia has shown the way 
out of this difficulty. Two of her four large centers — La Paz 
and Oruro — ^are connected by rail, and the line to Cochabamba 
lacks only a few kilometres of construction.^ To Sucre a line has 
been long projected. Formerly a revolution at one of the four 
towns was exceedingly difficult to stanip out. Diaz had the same 
double motive in encouraging railway building in the remote des- 
ert provinces of Northern Mexico, where nine out of ten Mexican 
revolutions gather headway. Argentina has enjoyed a high degree 
of political unity since her railway system was extended to 
Cordoba and Tucuman. The last uprising, that of 1906, took place 
on her remotest northeastern frontier. 

"We had ample opportunity to see the hatred of the rebels. At 
nightfall of September 25th we rode into the courtyard of Haci- 
enda Auquibamba. We had traveled under the worst possible 



'According to the latest information (August, 1916) of the Bolivia Railway Co., 
trains are running from Oruro to Buen Eetiro, 35 km. from Cochabamba. Thence 
connection with Cochabamba is made by a tram-line operated by the Electric Light and 
Power Co. of that city. The Bulletin of the Pan-American Union for July, 1916, 
also reports the proposed introduction of an automobile service for conveyance of 
freight and passengers. 



94 THE ANDES OF SOUTHERN PERU 

circumstances. Oui- mules had been enfeebled by hot valley 
work at Santa Ana and the lower Urubamba and the cold moun- 
tain climate of the Cordillera VilcajDampa. The climb out of the 
Apurimac canyon, even without packs, left them completely ex- 
hausted. We were obliged to abandon one and actually to iDull 
another along. It had been a hard day in spite of a prolonged 
noon rest. Everywhere our letters of introduction had won 
an outpouring of hospitality among a people to whom hospitality 
is one of the strongest of the unwritten laws of society. Our sol- 
dier escort rode ahead of the pack train. 

As the clatter of his mules' hoofs echoed through the dark 
buildings the manager rushed out, struck a light and demanded 
"Who's there?" To the soldier's cheerful "Buena noche, Seuor," 
he sneeringly replied "Halto! Guardia de la Repiibliea, aqui hay 
nada para un soldado del gobierno." Whereupon the soldier 
turned back to me and said we should not be able to stop here, 
and coming nearer me he whispered "He is a revolutionary." 
I dismounted and approached the haughty manager, who Avas 
in a really terrible mood. Almost before I could begin to 
ask him for accommodations he rattled off that there was no 
pasture for our beasts, no food for us, and that we had better 
go on to the next hacienda. ' ' Absolutamente nada ! " he re- 
peated over and over again, and at first I thought him drunk. 
Since it was then quite dark, with no moon, but instead hea\^ 
black clouds over the southern half of the sky and a brisk valley 
wind threatening rain, I mildly protested that we needed noth- 
ing more than shelter. Our food boxes would supply our wants, 
and our mules, even without fodder, could reach Abancay the 
next day. Still he stormed at the government and would have 
none of us. I reminded him that his fields were filled with 
sugar cane and that it was the staple forage for beasts during 
the part of the year when pasture was scarce. The cane was 
too valuable, he said. It was impossible to supply us. I was on 
the point of pitching camp beside the trail, for it was impossible 
to reach the next hacienda with an exhausted outfit. 

Just then an older man stepped into the circle of light and ami- 



THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 95 

ably inquired the purpose of our journey. When it was explained, 
he turned to the other and said it was unthinkable that men should 
be treated so inhospitably in a strange land. Though he himself 
was a gTiest he urged that the host should remember the laws of 
hospitality, whereupon the latter at last grudgingly asked us to join 
him at his table and to turn our beasts over to his servants. It was 
an hour or more before he would exhibit any interest in us. When 
he had learned of our object in visiting Abancay he became some- 
what more friendly, though his hostility still manifested itself. 
Nowhere else in South America have I seen exhibited such boorish 
conduct. Nevertheless the next morning I noticed that our mules 
had been well fed. He said good-by to us as if he were glad to 
be rid of any one in any way connected with the hostile govern- 
ment. Likewise the manager at Hacienda Pasaje held out almost 
until the last before he would consent to aid us with fresh beasts. 
Finally, after a day of courting I gave him a camp chair. He was 
so pleased that he not only gave us beasts, but also a letter of 
introduction to one of his caretakers on a farm at the top of the 
cuesta. Here on a cold, stormy night we found food and fuel and 
the shelter of a friendly roof. 

A by-product of the revolution, as of all revolutions in thinly 
settled frontier regions, was the organization of small bands of 
outlaws who infested the lonely trails, stole beasts, and left their 
owners robbed and helpless far from settlements. We were cau- 
tioned to beware of them, both by Seiior Gonzales, the Prefect at 
Abancay, and by the Subprefect of Antabamba, Since some of 
the bandits had been jailed, I could not doubt the accuracy of the 
reports, but I did doubt stories of murder and of raids by large 
companies of mountain bandits. As a matter of fact we were 
robbed by the Governor of Antabamba, but in a way that did not 
enable us to find redress in either law or lead. The story is worth 
telling because it illustrates two important facts : first, the vile 
so-called government that exists in some places in the really 
remote sections of South America, and second, the character of 
the mountain Indians. 

The urgent letter from the Prefect of Abancay to the Sub- 



96 THE ANDES OF SOUTHERN PERU 

prefect of Antabainba quickly brought the latter from his distant 
home. When we arrived we found him drinking with the Gov- 
ernor. -The Subprefect was most courteous. The Governor was 
good-natured, but his face exhibited a rare combination of cruelty 
and vice. We were offered quarters in the municipal building for 
the day or two that we were obliged to stop in the town. The 
delay enabled us to study the valley to whicli particular interest 
attaches because of its situation in the mountain zone between 
the lofty pastures of the Alpine country and the irrigated fields of 
the valley farmers. 

Antabamba itself lies on a smooth, high-level shoulder of the 
youthful Antabamba Valley. The valley floor is narrow and rocky, 
and affords little cultivable land. On the valley sides are steep 
descents and narrow benches, chiefly structural in origin, over 
which there is scattered a growth of scrub, sufficient to screen the 
deer and the bear, and, more rarely, vagrant bands of vicuiia that 
stray dovt^n from their accustomed haunts in the lofty Cordillera. 
Three thousand feet above the valley floor a broad shoulder be- 
gins (Fig. 60) and slopes gently up to the bases of the true moun- 
tains that surmount the broad rolling summit platform. Here are 
the great pasture lands of the Andes and their semi-nomadic shep- 
herds. The highest habitation in the world is located here at 
17,100 feet (5,210 m.), near a secondary pass only a few mUes 
from the main axis of the western chain, and but 300 feet (91 m.) 
below it. 

The people of Antabamba are both shepherds and farmers. 
The elevation is 12,000 feet (3,658 m.), too high and exposed for 
anything more than potatoes. Here is an Indian population pure- 
blooded, and in other respects, too, but little altered from its 
original condition. There is almost no communication Avith the 
outside world. A deep canyon fronts the town and a lofty moun- 
tain range forms the background. 

At nightfall, one after another, the Indians came in from tlie 
field and doffed their caps as they passed our door. Finally came 
the "Teniente Gobernador," or Lieutenant Governor. He had 
only a slight strain of white blood. His bearing was that of n 



THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 97 

sneak, and he confirmed this impression by his frank disdain for 
Ms full-blooded townsmen. "How ragged and ugly they are! 
You people must find them very stupid, ' ' etc. When he found that 
we had little interest in his remarks, he asked us if we had ever 
seen Lima. We replied that we had, whereupon he said, "Do you 
see the gilded cross above the church yonder? I brought that on 
muleback all the way from Lima! Think of it! These ignorant 
people have never seen Lima!" His whole manner as he drew 
himself up and hit his breast was intended to make us think that 
he was vastly superior to his neighbors. The sequel shows that 
our first estimate of him was correct. 

We made our arrangements with the Governor and departed. 
To inspire confidence, and at the Governor's urgent request, we 
had paid in advance for our four Indians and our fresh beasts — 
and at double the usual rates, for it was still winter in the 
Cordillera. They were to stay with us until we reached Cota- 
huasi, in the next Department beyond the continental divide, 
where a fresh outfit could be secured. The Lieutenant Governor 
accompanied us to keep the party together. They appeared to 
need it. Like our Indian peons at Lambrama the week before, 
these had been taken from the village jail and represented the 
scum of the town. As usual they behaved well the first day. On the 
second night we reached the Alpine country where the vegetation 
is very scanty and camped at the only spot that offered fuel and 
water. The elevation was 16,000, and here we had the lowest tem- 
perature of the whole journey, + 6° F. ( — 14.4° C). Ice covered 
the brook near camp as soon as the sun went down and all night 
long the Avind blew down from the lofty Cordillera above us, bring- 
ing flurries of snow and tormenting our unprotected beasts. It 
seemed to me doubtful if our Indians would remain. I discussed 
with the other members of the party the desirability of chaining 
the peons to the tent pole, but this appeared so extreme a measure 
that we abandoned the idea after warning the Teniente that he 
must not let them escape. " 

At daybreak I was alarmed at the unusual stillness about 
camp. A glance showed that half our hobbled beasts had 



98 THE ANDES OF SOUTHERN PERU 

drifted back toward Antabamba and no doubt were now miles 
away. The four Indian peons had left also, and their tracks, 
half buried by the last snowfall, showed that they had left 
hours before and that it was useless to try to overtake them. 
Furthermore we were making a topographic map across the 
Cordillera, and, in view of the likelihood of snow blockading 
the 17,600-foot (5,360 m.) pass which we had to cross, the work 
ought not to be delayed. With all these disturbing conditions to 
meet, and suffering acutely from mountain sickness, I could 
scarcely be expected to deal gently with our official. I drew out 
the sleeping Teniente and set him on his feet. To my inquiry 
as to the whereabouts of the Indians that he had promised to 
guard, he blinked uncertainly, and after a stupid "Quien sabe?" 
peered under the cover of a sheepskin near by as if the peons had 
been transformed into insects and had taken refuge under a blade 
of grass. I ordered him to get breakfast and after that to take 
upon his back the instruments that two men had carried up to 
that time, and accompany the topographer. Thus loaded, the 
Lieutenant Governor of Antabamba set out on foot a little ahead 
of the party. Hendriksen, the topographer, directed him to a 
17,000-foot peak near camp, one of the highest stations occupied in 
the traverse. When the topographer reached the summit the in- 
struments were there but the Teniente had fled. Hendriksen rap- 
idly followed the tracks down over the steep snow-covered wall of 
a deeply recessed cirque, but after a half -hour's search could not 
get sight of the runaway, whereupon he returned to his station 
and took his observations, reaching camp in the early afternoon. 
In the meantime I had intercepted two Indians who had come 
from Cotahuasi driving a llama train loaded with corn. They held 
a long conversation at the top of the pass above camp and at first 
edged suspiciously away. But the rough ground turned them 
back into the trail and at last they came timidly along. They pre- 
tended not to understand Spanish and protested vigorously that 
they had to keep on with their llamas. I thought from the bel- 
ligerent attitude of the older, which grew rapidly more threaten- 
ing as he saw that I was alone, that I was in for trouble, but when 



THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 99 

I drew my revolver he quickly obeyed the order to sit down to 
breakfast, which consisted of soup, meat, and army biscuits. I 
also gave them coca and cigarettes, the two most desirable gifts 
one can make to a plateau Indian, and thereupon I thought I had 
gained their friendship, for they at last talked with me in broken 
Spanish. The older one now explained that he must at all hazards 
reach Matara by nightfall, but he would be glad to leave his son 
to help us. I agreed, and he set out forthwith. The arriero 
(muleteer) had now returned with the lost mules and with the as- 
sistance of the Indian we soon struck camp and loaded our mules. 
I cautioned the arriero to keep close watch of the Indian, for at 
one time I had caught on his face an expression of hatred more in- 
tense than I had ever seen before. The plateau Indian of South 
America is usually so stupid and docile that the unexpectedly 
venomous look of the man after our friendly conversation and my 
good treatment alarmed me. At the last moment, and when our 
backs were turned, our Indian, under the screen of the packs, 
slipped away from us. The arriero called out to know where he 
had gone. It took us but a few moments to gain the top of a hill 
that coramanded the valley. Fully a half-mile away and almost 
indistinguishable against the brown of the valley iloor was our 
late assistant, running like a deer. No mule could follow over that 
broken ground at an elevation of 16,000 feet, and so he escaped. 

Fortunately that afternoon we passed a half-grown boy riding 
back toward Antabamba and he promised to hand the Governor 
a note in Spanish, penciled on a leaf of my traverse book. I 
dropped all the polite phrases that are usually employed and wrote 
as follows : 

" Senor Gobernador : 

" Your Indians have escaped, likewise the Lieutenant Governor." They have 
taken two beasts. In the name of the Prefect of Abancay, I ask you immediately 
to bring a fresh supply of men and animals. We shall encamp near the first pass, 
three days west of Antabamba, until you come." 

We were now without Indians to carry the instruments, which 
had therefore to be strapped to the mules. Without guides we 
started westward along the trail. At the next pass the topog- 



100 THE ANDES OF SOUTHERN PERU 

rapher rode to the summit of a bluff and asked which of tlae two 
trails I intended to follow. Just then a solitary Indian passed 
and I shouted back that I would engage the Indian and precede 
the party, and he could tell from my course at the fork of the 
trail how to direct his map and where to gain camp at nightfall. 
But the Indian refused to go with us. All my threatening was 
useless and I had to force myself to beat him into submission with 
my quirt. Several repetitions on the way, when he stubbornly re- 
fused to go further, kept our guide with us until we reached a 
camp site. I had offered him a week's pay for two hours' work, 
and had put coca and cigarettes into his hands. "When these 
failed I had to resort to force. Now that he was about to leave I 
gave him double the amount I had promised him. He could 
scarcely believe his eyes. He rushed up to the side of my mule, 
and reaching around my waist embraced me and thanked me 
again and again. The plateau Indian is so often waylaid in the 
mountains and impressed for service, then turned loose without 
pay or actually robbed, that a promise to pay holds no attraction 
for him. I had up to the last moment resembled this class of 
white. He was astonished to find that I really meant to pay him 
well. 

Then he set out upon the return, faithfully delivering my note 
to the topographer about the course of the trail and the position 
of the camp. He had twelve miles to go to the first mountain hut, 
so that he could not have traveled less than that distance to reach 
shelter. The nest morning a mantle of snow covered everj'thing, 
yet when I pushed back the tent flap there stood my scantily clad 
Indian of the night before, shivering, with sandaled feet in the 
snow, saying that he had come back to work for me ! 

This camp was number thirteen out of Abancay, and here our 
topographer was laid up for three days. Heretofore the elevation 
had had no effect upon him, but the excessively lofty stations of 
the past few days and the hard climbing had finally prostrated 
him. We had decided to carry him out by the fourth day if he 
felt no better, but happily he recovered sufficiently to continue the 
work. The delay enabled the Governor to overtake us with a fresh 



THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 101 

outfit. On the morning of our third day in camp he overtook us 
with a small escort of soldiers accompanied by the fugitive 
Teniente. He said that he had come to arrest me on the charge of 
maltreating an official of Peru. A few packages of cigarettes and 
a handful of raisins and biscuits so stirred his gratitude that we 
parted the best of friends. Moreover he provided us with four 
fresh beasts and four new men, and thus equipped we set out for 
a rendezvous about ten miles away. But the faithless Governor 
turned off the trail and sought shelter at the huts of a company 
of mountain shepherds. That night his men slept on the ground 
in a bitter wind just outside our camp at 17,200 feet. They com- 
plained that they had no food. The Governor had promised to 
join us with llama meat for the peons. We fed them that night 
and also the next day. But we had by that time passed the crest 
of the western Cordillera and were outside the province of Anta- 
bamba. The next morning not only our four men but also our 
four beasts were missing. We were stranded and sick just under 
the pass. To add to our distress the surgeon, Dr. Erving, was 
obliged to leave us for the return home, taking the best saddle 
animal and the strongest pack mule. It was impossible to go on 
with the map. That morning I rode alone up a side valley until 
I reached a shepherd's hut, where I could find only a broken-down, 
shuffling old mule, perfectly useless for our hard work. 

Then there happened a piece of good luck that seems almost 
providential. A young man came down the traU with three pack 
mules loaded with llama meat. He had come from the Cotahuasi 
Valley the week before and knew the trail. I persuaded him to 
let us hire one of his mules. In this way and by leaving the in- 
struments and part of our gear in the care of two Indian youths 
we managed to get to Cotahuasi for rest and a new outfit. 

The young men who took charge of part of our outfit interested 
me very greatly. I had never seen elsewhere so independent and 
clear-eyed a pair of mountain Indians. At first they would have 
nothing to do with us. They refused us permission to store our 
goods in their hut. To them we were railroad engineers. They 
said that the railway might come and when it did it would depopu- 



102 THE ANDES OF SOUTHERN PERU 

late the country. The railway was a curse. Natives were obliged 
to work for the company without pay. Their uncle had told them 
of frightful abuses over at Cuzco and had warned them not to 
help the railway people in any way. They had moved out here 
in a remote part of the mountains so that white men could not 
exploit them. 

In the end, however, we got them to understand the nature of 
our work. Gifts of various sorts won their friendship, and they 
consented to guard the boxes we had to leave behind. Two weeks 
later, on his return, the topographer found evei-ything unmolested. 

I could not but feel that the spirit of those strong and inde- 
pendent young men was much better for Peru than the cringing, 
subservient spirit of most of the Indians that are serfs of the 
whites. The policy of the whites has been to suppress and ex- 
ploit the natives, to abuse them, and to break their spirit. They 
say that it keeps down revolution; it keeps the Indian in his place. 
But certainly in other respects it is bad for the Indian and it is 
worse for the whites. Their brutality toward the natives is in- 
credible. It is not so much the white himself as the vicious half- 
breed who is often allied with him as his agent. 

I shall never forget the terror of two young girls driving a don- 
key before them when they came suddenly face to face with our 
party, and we at the same time hastily scrambled off our beasts 
to get a photograph of a magnificent view disclosed at the bend 
of the steep trail. They thought we had dismounted to attack 
them, and fled screaming in abject fear up the mountain side, 
abandoning the donkey and the pack of potatoes which must have 
represented a large part of the season's product. It is a kind of 
highway robbery condoned because it is only robbing an Indian. 
He is considered to be lawful prey. His complaint goes unnoticed. 
In the past a revolution has offered him sporadic chances to wreak 
vengeance. More often it adds to his troubles by scattering 
through the mountain valleys the desperate refugees or lawless 
bands of marauders who kill the flocks of the mountain shepherds 
and despoil their women. 

There are still considerable numbers of Indians who shun the 



THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 103 

white man and live in the most remote corners of the mountains. 
1 have now and again come upon the most isolated huts, invisible 
from the valley trails. They were thatched with grass ; the walls 
were of stone; the rafters though light must have required pro- 
digious toil, for all timber stops at 12,000 feet on the mountain 
borders. The shy fugitive who perches his hut near the lip of a 
hanging valley far above the trail may look down himself unseen 
as an eagle from its nest. When the owner leaves on a journey, 
or to take his flock to new pastures, he buries his pottery or hides 
it in almost inaccessible caves. He locks the door or bars it, thank- 
ful if the spoiler spares rafters and thatch. 

At length we reached Cotahuasi, a town sprawled out on a ter- 
race just above the floor of a deep canyon (Fig. 29) . Its flower gar- 
dens and pastures are watered by a multitude of branching canals 
lined with low willows. Its bright fields stretch up the lower 
slopes and alluvial fans of the canyon to the limits of irrigation 
where the desert begins. The fame of this charming oasis is wide- 
spread. The people of Antabamba and Lambrama and even the 
officials of Abancay spoke of Cotahuasi as practically the end of 
our journey. Fruits ripen and flowers blossom every month 
of the year. Where we first reached the canyon floor near 
Huaynacotas, elevation 11,500 feet (3,500 m.), there seemed to be 
acres of rose bushes. Only the day before at an elevation of 
16,800 feet (5,120 m.) we had broken thick ice out of a mountain 
spring in order to get water ; now we were wading a shallow river, 
and grateful for the shade along its banks. Thus we came to the 
town prepared to find the people far above their plateau neigh- 
bors in character. Yet, in spite of friendly priests and officials 
and courteous shopkeepers, there was a spirit strangely out of 
harmony with the pleasant landscape. 

Inquiries showed that even here, where it seemed that only 
sylvan peace should reign, there had recently been let loose the 
spirit of barbarism. We shall turn to some of its manifestations 
and look at the reasons therefor. 

In the revolution of 1911 a mob of drunken, riotous citizens 
gathered to storm the Cotahuasi barracks and the jail. A full- 



104- THE ANDES OF SOUTHERN PERU 

blooded Indian soldier, on duty at the entrance, ordered the rioters 
to stop and when they paid no heed he shot the leader and scat- 
tered the crowd. The captain thereupon ordered the soldier to 
Arequipa because his life was no longer safe outside the barracks. 
A few naonths later he was assigned to Professor Bingham's 
Coropuna expedition. Professor Bingham reached the Cotahuasi 
Valley as I was about to leave it for the coast, and the soldier was 
turned over to me so that he might leave Cotahuasi at the earliest 
possible moment, for his enemies were plotting to kill him. 

He did not sleep at all the last night of his stay and had us 
called at three in the morning. He told his friends that he was 
going to leave with us, but that they were to announce his leav- 
ing a day later. In addition, the Subprefect was to accompany 
us until daybreak so that no harm might befall me while under 
the protection of a soldier who expected to be shot from ambush. 

At four o'clock our whispered arrangements were made, Ave 
opened the gates noiselessly, and our small cavalcade hurried 
through the pitch-black streets of the town. The soldier rode 
ahead, his rifle across his saddle, and directly behind him rode 
the Subprefect and myself. The pack mules were in the rear. We 
had almost reached the end of the street when a door opened sud- 
denly and a shower of sparks flew out ahead of us. Instantly the 
soldier struck spurs into his mule and turned into a side street. 
The Subprefect drew his horse back savagely and when the nest 
shower of sparks flew out pushed me against the wall and 
whispered: "Por Dios, quien es?" Then suddenly he shouted: 
"Sopla no mas, sopla no mas" (stop blowing). 

Thereupon a shabby penitent man came to the door holding in 
his hand a large tailor's flatiron. The base of it was filled with 
glowing charcoal and he was about to start his day's work. The 
sparks were made in the process of blowing through the iron to 
start the smoldering coals. We greeted him A\dth more than 
ordinary friendliness and passed on. 

At daybreak we had reached the steep western wall of the 
canyon where the real ascent begins, and here the Subprefect 
turned back with many felicidades for the journey and threats 



THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 105 

for the soldier if he did not look carefully after the pack train. 
From every angle of the zigzag trail that climbs the "cuesta" the 
soldier scanned the valley road and the trail below him. He was 
anxious lest news of his escape reach his enemies who had vowed 
to take his life. Half the day he rode turned in his saddle so as 
to see every traveler long before he was within harm's reach. By 
nightfall we safely reached Salamanca, fifty miles away (Fig. 62). 

The alertness of the soldier was unusual and I quite enjoyed 
his close attention to the beasts and his total abstinence, for an 
alert and sober soldier on detail is a rare phenomenon in the in- 
terior of Peru. But all Salamanca was drunk when we arrived 
— Governor, alcaldes, citizens. Even the peons drartk up in brandy 
the money that we gave them for forage and let the beasts starve. 
The only sober person I saw was the white telegraph operator 
from Lima. He said that he had to stay sober, for the telegraph 
office — ^the outward sign of government — ^was the special object 
of attack of every drink-crazed gang of rioters. They had tried 
to break in a few nights before and he had fired his revolver point- 
blank through the door. The town offered no shelter but the dark 
filthy hut of the Gobernador and the tiny telegraph office. So I 
made up my bed beside that of the operator. "We shared our meals 
and chatted until a late hour, he recounting the glories of Lima, 
to which he hoped to return at the earliest possible moment, and 
cursing the squalid town of Salamanca. His operator's keys were 
old, the batteries feeble, and he was in continual anxiety lest a 
message could not be received. In the night he sprang out of bed 
shouting frantically : 

"Estan llamando" (they are calling), only to stumble over my. 
bed and awaken himself and offer apologies for walking in his 
sleep. 

Meanwhile my soldier, having regained his courage, began 
drinking. It was with great difficulty that I got started, after a 
day's delay, on the trail to Chuquibamba. There his thirst quite 
overcame him. To separate him from temptation it became nec- 
essary to lock him up in the village jail. This I did repeatedly on 
the way to Mollendo, except beyond Quilca, where we slept in the 



106 THE ANDES OF SOUTHERN PERU 

hot marshy valley out of reach of drink, and where the mosquitoes 
kept us so busy that either eating or drinking was almost out of 
the question. 

The drunken rioters of Cotahuasi and their debauched brothers 
at Salamanca are chiefly natives of pure or nearly pure Indian 
blood. They are a part of the great plateau population of the 
Peruvian Andes. Have they degenerated to their present low 
state, or do they display merely the normal condition of the 
plateau people? Why are they so troublesome an element? To 
this as to so many questions that arise concerning the highland 
population we find our answer not chiefly in government, or re- 
ligion, or inherited character, but in geography. I doubt very 
much if a greater relative difference would be seen if two groups 
of whites were set down, the one in the cold terr.ace lands of 
Salamanca, the other in the warm vineyards of Aplao, in the Majes 
Valley. The common people of these two towns were originally 
of the same race, but the lower valley now has a white element 
including even most of those having the rank of peons. Greater 
differences in character could scarcely be found between the Aztecs 
and the Iroquois. In the warm valley there is of coarse drunken- 
ness, but it is far from general ; there is stupidity, but the people 
are as a whole alert; and finally, the climate and soil produce 
grapes from which famous wines are made, they produce sugar 
cane, cotton, and alfalfa, so that the whites have come in, diluted 
the Indian blood, and raised the standard of life and behavior. 
Undoubtedly their influence would tend to have the same general 
effect if they mixed in equal numbers with the plateau groups. 
There is, however, a good reason for their not doing so. 

The lofty towns of the plateau have a really wretched climate. 
White men cannot live comfortably at Antabamba and Salamanca. 
Further, they are so isolated that the modest comforts and the 
smallest luxuries of civilization are very expensive. To pay for 
them requires a profitable industry managed on a large scale and 
there is no such industry in the higher valleys. The white who 
goes there must be satisfied to live like an Indian. The result is 
easy to forecast. Outside of government officers, only the disso- 




Fig. 60. 




Fig. G1. 



Fig. 00 — View across the Antabaiiiba canyon jnst above Huadquirca. 
Fig. 61 — Hnancarama, west of Abancay, on the famous Lima to Buenos Aires 
road. Note the smooth slopes in the foreground. See Chapter XI. 




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THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 107 

lute or unsuccessful whites live in the worst towns, like Salamanca 
and Antabamba. A larger valley with a slightly milder climate 
and more accessible situation, like Chuquibamba, will draw a still 
better grade of white citizen and in the largest of all — Cuzco and 
the Titicaca basin — ^we find normal whites in larger numbers, 
though they nowhere live in such high ratios to the Indian as on 
the coast and in the lower valleys near the coast. With few ex- 
ceptions the white population of Peru is distributed in response 
to favorable combinations of climate, soil, accessibility, and gen- 
eral opportunities to secure a living without extreme sacrifice. 

These facts are stated in a simple way, for I wish to emphasize 
the statement that the Indian population responds to quite other 
stimuli. Most of the luxuries and comforts of the whites mean 
nothing to the Indian. The machine-made woolens of the im- 
porters will probably never displace his homespun llama-wool 
clothing. His implements are few in number and simple in form. 
His tastes in food are satisfied by the few products of his fields 
and his mountain flocks. Thus he has lived for centuries and is 
quite content to live today. Only coca and brandy tempt him to 
engage in commerce, to toil now and then in the hot valleys, and 
to strive for more than the bare necessities of life. Therefore 
it matters very little to him if his home town is isolated, or the 
resources support but a small group of people. He is so ac- 
customed to a solitary existence in his ramblings with his flocks 
that a village of fifty houses offers social enjoyments of a high 
order. Where a white perishes for lack of society the Indian finds 
himself contented. Finally, he is not subject to the white man's 
exploitation when he lives in remote places. The pastures are ex- 
tensive and free. The high valley lands are apportioned by the 
alcalde according to ancient custom. His life is unrestricted by 
anything but the common law and he need have no care for the 
morrow, for the seasons here are almost as fixed as the stars. 

Thus we have a sort of segregation of whites in the lower 
places where a modern type of life is maintained and of Indians 
in the higher places where they enjoy advantages that do not ap- 
peal to the whites. Above 8,000 feet the density of the white popu- 



108 THE ANDES OF SOUTHERN PERU 

lation bears a close inverse proportion to the altitude, excepting 
in the case of the largest valleys whose size brings together such 
numbers as to tempt the commercial and exploiting whites to live 
in them. Furthermore, we should find that high altitude, limited 
size, and greater isolation are everyAvhere closely related to in- 
creasing immorality or decreasing character among the whites. So 
to the low Indian population there is thus added the lowest of the 
white population. Moreover, because it yields the largest returns, 
the chief business of these whites is the sale of coca and brandy 
and the downright active debauchery of the Indian. This is all 
the easier for them because the isolated Indian, like the average 
isolated white, has only a low and provincial standard of morality 
and gets no help from such stimulation as numbers usually excite. 

For example, the Anta basin at harvest time is one of the fair- 
est sights in Peru. Sturdy laborers are working diligently. Their 
faces are bright and happy, their skin clear, their manner eager 
and animated. They sing at their work or gather about their mild 
chicha and drink to the patron saints of the harvest. The huts are 
filled with robust children ; all the yards are turned into threshing 
floors; and from the stubbly hillslopes the shepherd blows shrill 
notes upon his barley reeds and bamboo flute. There is drinking 
but there is little disorder and there is always a sober remnant 
that exercises a restraining influence upon the group. 

In the most remote places of all one may find mountain groups 
of a high order of morality unaffected by the white man or actu- 
ally shunning him. Clear-eyed, thick-limbed, independent, a fine, 
sturdy type of man this highland shepherd may be. But in the 
town he succumbs to the temptation of drink. Some writers have 
tried to make him out a superior to the plains and low valley type. 
He is not that. The well-regulated groups of the lower elevations 
are far superior intellectually and morally in spite of the fact that 
the poorly regulated groups may fall below the highland dweller 
in morality. The coca-chewing highlander is a clod. Surelj^ as 
a whole, the mixed breed of the coastal valleys is a far worthier 
type, save in a few cases where a Chinese or negroid element or 
both have led to local inferiority. And surely, also, that is the 



THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 109 

worst combination which results in adding the viciousness of the 
inferior or debased white to the stupidity of the highland Indian. 
It is here that the effects of geography are most apparent. If the 
white is tempted in large numbers because of exceptional position 
or resources, as at La Paz, the rule of altitude may have an escep- 
tion. And other exceptions there are not due to physical causes, 
for character is practically never a question of geography alone. 
There is the spiritual factor that may illumine a strong character 
and through his agency turn a weak community into a powerful 
one, or hold a weakened group steadfast against the forces of dis- 
integration. Exceptions arise from this and other causes and yet 
with them all in mind the geographic factor seems predominant in 
the types illustrated herewith.- 

' During his travels Raimondi collected many instances of the isolation and con- 
servatism of the plateau Indian: thus there is the village of Pampacolca near Coro- 
puna, whose inhabitants until recently carried their tdols of clay to the slopes of the 
great white mountain and worshiped them there with the ritual of Inca days (El Peru, 
Lima, 1874, Vol. 1). 



> 



CHAPTER VIII 
THE COASTAL DESERT 

To the wayfarer frora the bleak mountains the warm green val- 
leys of the coastal desert of Peru seem like the climax of scenic 
beauty. The streams are intrenched from 2,000 to 4,000 feet, and 
the valley walls in some places drop 500 feet by sheer descents 
from one level to another. The cultivated fields on the valley 
floors look like sunken gardens and now and then one may catch 
the distant glint of sunlight on water. The broad white path that 
winds through vineyards and cotton-fields, follows the foot of a 
cliff, or fills the whole breadth of a gorge is the waste-strewn, 
half-dry channel of the river. In some places almost the whole floor 
is cultivated from one valley wall to the other. In other places 
the fields are restricted to narrow bands between the river and the 
impending cliffs of a narrow canyon. Where tributaries enter 
from the desert there may be huge banks of mud or broad triangu- 
lar fans covered with raw, infertile earth. The picture is gener- 
ally touched with color — a yellow, haze-covered horizon on the bare 
desert above, brown lava flows suspended on the brink of the val- 
ley, gray-brown cliffs, and greens ranging from the dull shade of 
algarrobo, olive and fig trees, to the bright shade of freshly irri- 
gated alfalfa pastures. 

After several months' work on the cold highlands, Avhere we 
rode almost daily into hailstorms or wearisome gales, we came at 
length to the border of the valley country. It will always seem to 
me that the weather and the sky conspired that afternoon to re- 
ward us for the months of toil that lay behind. And certainly 
there could be no happier place to receive the reward than on the 
brink of the lava plateau above Chuquibamba. There was prom- 
ise of an extraordinary view in the growing beauty of the sky, 
and we hurried our tired beasts forward so that the valley below 

110 








Fig. 63 




Fig. 63— The deep fertile Majes Valley below Cantas. Compare with Fig. 6 show- 
ing the Chili Valley at Arequipa. 

Fig. 64— The Majes Valley, desert coast, western Peru. The lighter patches on the 
valley floor are the gravel beds of the river at high water. Much of the alluvial land 
is still uncleared. 



THE COASTAL DESERT 111 

might also be included in the picture. The head of the Majes Val- 
ley is a vast hollow bordered by cliffs hundreds of feet high, and 
we reached the rim of it only a few minutes before sunset. 

I remember that we halted beside a great wooden cross and 
that our guide, dismounting, walked up to the foot of it and kissed 
and embraced it after the custom of the mountain folk when they 
reach the head of a steep "cuesta." Also that the trail seemed 
to drop off like a stairway, which indeed it was.^ Everything else 
about me was completely overshadowed by snowy mountains, col- 
ored sky, and golden-yellow desert. One could almost forget the 
dark clouds that gather around the great mass of Coropuna and 
the bitter winds that creep down from its glaciers at night — it 
seemed so friendly and noble. Behind it lay bulky masses of rose- 
tinted clouds. We had admired their gay colors only a few min- 
utes, when the sun dropped behind the crest of the Coast Eange 
and the last of the sunlight played upon the sky. It fell with such 
marvelously swift changes of color upon the outermost zone of 
clouds as these were shifted with the wind that the eye had 
scarcely time to comprehend a tint before it was gone and one 
more beautiful still had taken its place. The reflected sunlight 
lay warm and soft upon the white peaks of Coropuna, and a little 
later the Alpine glow came out delicately clear. 

When we turned from this brilliant scene to the deep valley, 
we found that it had already become so dark that its greens had 
turned to black, and the valley walls, now in deep shadow, had lost 
half their splendor. The color had not left the sky before the 
lights of Chuquibamba began to show, and candles twinkled from 
the doors of a group of huts close under the cliff. We were not 
long in starting the descent. Here at last were friendly habita- 
tions and happy people. I had worked for six weeks between 
12,000 and 17,000 feet, constantly ill from mountain sickness, and 
it was with no regret that I at last left the plateau and got down 



^ Raimondi (op. cit., p. 109) has a characteristic description of the " Camino del 
PeSon " in the department of La Libertad : " . . . the ground seems to disappear from 
one's feet; one is standing on an elevated balcony looking down more than 6,000 feet 
to the valley . . . the road which descends the steep scarp is a masterpiece." 



112 



THE ANDES OF SOUTHERN PERU 



to comfortable altitudes. It seemed good news when the guide 
told me that there were mosquitoes in the marshes of Camana. 
Any low, hot land would have seemed like a health resort. I had 
been in the high country so long that, like the Bolivian mining 
engineer, I wanted to get down not only to sea level, but below it ! 
If the reader will examine Figs. 65 and 66, and the photographs 
that accompany them, he may gain an idea of the more important 




Fig. 65 — Regional diagram to show the physical relations in the coastal desert 
of Peru. For location, see Fig. 20. 

features of the coastal region. We have already described, in 
Chapters V and VII, the character of the plateau region and its 
people. Therefore, we need say little in this place of the part 
of the Maritime CordiUera that is included in the figure. Its 
unpopulated rim (see p. 54), the semi-nomadic herdsmen and shep- 
herds from Chuquibamba that scour its pastures in the moist 
vales about Coropuna, and the gnarled and stunted trees at 13,000 
feet (3,960 m.) which partly supply Chuquibamba with firewood, 
are its most important features. A few groups of huts just under 
the snowline are inhabited for only a part of the year. The de- 
lightful valleys are too near and tempting. Even a plateau 
Indian responds to the call of a dry valley, however he may shun 
the moist, warm valleys on the eastern border of the Cordillera. 



THE COASTAL DESERT 



113 




Fig. 66 — Irrigated and irrigable land of the coastal belt of Peru. The map ex- 
hibits in a striking manner how small a part of the whole Pacific slope is available for 
cultivation. Pasture grows over all but the steepest and the highest portions of the 
Cordillera to the right of (above) the dotted line. Another belt of pasture too nar- 
row to show on the map, grows in the fog belt on the seaward slopes of the Coast 
Range. Scale, 170 miles to the inch. 



114. THE ANDES OF SOUTHERN PERU 

The greater part of the coastal region is occupied by the des- 
ert. Its outer border is the low, dry, gentle, eastward-facing slope 
of the Coast Eange. Its inner border is the foot of the steep 
descent that marks the edge of the lava plateau. This descent is 
a fairly well-marked line, here and there broken by a venturesome 
lava flow that extends far out from the main plateau. Within 
these definite borders the desert extends continuously northwest- 
ward for hundreds of miles along the coast of Peru from far be- 
yond the Chilean frontier almost to the border of Ecuador. It is 
broken up by deep tranverse valleys and canyons into so-called 
"pampas," each of which has a separate name; thus west of 
Arequipa between the Vitor and Majes valleys are the "Pampa 
de Vitor" and the "Pampa de Sihuas," and south of the Vitor 
is the "Pampa de Islay." 

The pampa surfaces are inclined in general toward the sea. 
They were built up to their present level chiefly by mountain 
streams before the present deep valleys were cut, that is to say, 
when the land was more than a half-mile lower. Some of their 
material is Avind-blown and on the walls of the valleys are alter- 
nating belts of wind-blown and water-laid strata from one hun- 
dred to four hundred feet thick as if in past ages long dry and 
long wet periods had succeeded each other. The wind has blown 
sand and dust from the desert down into the valleys, but its chief 
work has been to drive the lighter desert waste up partly into the 
mountains and along their margins, partly so high as to carry it 
into the realm of the lofty terrestrial winds, whence it falls upon 
surfaces far distant from the fields of origin. There are left 
behind the heavier sand which the wind rolls along on the sur- 
faces and builds into crescentic dunes called medanos, and the peb- 
bles that it can sandpaper but cannot remove bodily. Thus there 
are belts of dunes, belts of irregular sand drifts, and belts of true 
desert "pavement" (a residual mantle of faceted pebbles and 
irregular stones). 

Yet another feature of the desert pampa are the "dry" val- 
leys that join the through-flowing streams at irregular intervals, 
as shown in the accompanying regional diagram. If one follow 



72-30' 




6°20' 



12'30' 



ENS. AND PTG. BV THE TOPOGRAPHIC EfJGRAVrtJG CO. WASH„D.t 

Edition of 1916 



IS' so' 



THE YALS. PERUVIAN EXPEDITIOK 

K:pj-2.t BmasAu, directop. 




THE COASTAL DESERT 115 

a dry valley to its head he will find there a set of broad and shal- 
low tributaries. Sand drifts may clog them and appear to indi- 
cate that water no longer flows through them. They are often re- 
ferred to by unscientific travelers as evidences of a recent change 
of climate. I had once the unusual opportunity (in the mountains 
of Chile) of seeing freshly fallen snow melted rapidly and thus 
turned suddenly into the streams. In 1911 this happened also at 
San Pedro de Atacama, northern Chile, right in the desert at 
8,000 feet (2,440 m.) elevation, and in both places the dry, sand- 
choked valleys were cleaned out and definite channels reestab- 
lished. From a large number of facts like these we know that the 
dry valleys represent the work of the infrequent rains. No desert 
is absolutely rainless, although until recently it was the fashion 
to say so. Naturally the wind, which works incessantly, partly 
offsets the work of the water. Yet the wind can make but little 
impression upon the general outlines of the dry valleys. They re- 
main under the dominance of the irregular rains. These come 
sometimes at intervals of three or four years, again at intervals 
of ten to fifteen years, and some parts of the desert have probably 
been rainless for a hundred years. Some specific cases are dis- 
cussed in the chapter on Climate. 

The large valleys of the desert zone have been cut by snow- 
fed streams and then partly filled again so that deep waste lies on 
their floors and abuts with remarkable sharpness against the bor- 
dering cliffs (Fig. 155). Extensive flats are thus available for 
easy cultivation, and the through-flowing streams furnish abundant 
water to the irrigating canals. The alluvial floor begins almost 
at the foot of the steep western slope of 'the lava plateau, but it is 
there stony and coarse — hence Chuquibamba, or plain of stones 
(chuqui=stone ; bamba=plain) . Farther down and about half-way 
between Chuquibamba and Aplao (Camana Quadrangle) it is partly 
covered with fresh mud and sand flows from the bordering valley 
walls and the stream is intrenched two hundred feet. A few miles 
above Aplao the stream emerges from its narrow gorge and thence- 
forth flows on the surface of the alluvium right to the sea. Nar- 
row places occur between Cantas and Aplao, where there is a pro- 



116 THE ANDES OF SOUTHERN PERU 

jection of old and hard quartzitic rock, and again above Camana, 
where the stream cuts straight across the granite axis of the Coast 
Eange. Elsewhere the rock is either a softer sandstone or still 
unindurated sands and gravels, as at the top of the desert series 
of strata that are exposed on the valley wall. The changing width 
of the valley is thus a reflection of the changing hardness of the 
rock. 

There is a wide range of products between Chuquibamba at 
10,000 feet (3,050 m.) at the head of the valley and Camana near 
the valley mouth. At the higher levels fruit will not grow — only 
alfalfa, potatoes, and barley. A thousand feet below Chuqui- 
bamba fruit trees appear. Then follows a barren stretch where 
there are mud flows and where the river is intrenched. Below 
this there is a wonderful change in climate and products. The 
elevation falls off 4,000 feet and the first cultivated patches 
below the middle unfavorable section are covered -with grape 
vines. Here at 3,000 feet (900 m.) elevation above the sea begin 
the famous vineyards of the Majes Valley, which support a wine 
industry that dates back to the sixteenth century. Some of the 
huge buried earthenware jars for curing the wine at Hacienda 
Cantas were made in the reign of Philip II. 

The people of Aplao and Camana are among the most hospita- 
ble and energetic in Peru, as if these qualities were but the re- 
flection of the bounty of nature. Nowhere could I see evidences 
of crowding or of the degeneracy or poverty that is so often as- 
sociated with desert people. Water is always plentiful; some- 
times indeed too plentiful, for floods and changes in the bed of 
the river are responsible for the loss of a good deal of land. 
This abundance of water means that both the small and the large 
landowners receive enough. There are none of the troublesome 
ofificial regulations, as in the poorer valleys with their inevitable 
favoritism or doAvnright graft. Yet even here the valley is not 
fully occupied; at many places more land could be put under 
cultivation. The Belaunde brothers at Cantas have illustrated 
this in their new cotton plantation, where clearings and new canals 
have turned into cultivated fields tracts long covered with brush. 



THE COASTAL DESERT 117 

The Majes Valley sorely lacks an adequate port. Its cotton, 
sugar, and wine must now be shipped to Camana and thence to 
MoUendo, either by a small bi-weekly boat, or by pack-train over 
the coast trail to Quilca, where ocean steamers call. This is so 
roundabout a way that the planters of the mid-valley section and 
the farmers of the valley head now export their products over the 
desert trail from Cantas to Vitor on the MoUendo-Arequipa rail- 
road, whence they can be sent either to the cotton mills or the 
stores of Arequipa, the chief distributing market of southern 
Peru, or to the ocean port. 

The foreshore at Camana is low and marshy where the salt 
water covers the outer edge of the delta. In the hollow between 
two headlands a broad alluvial plain has been formed, through 
which the shallow river now discharges. Hence the natural inden- 
tation has been filled up and the river shoaled. To these disad- 
vantages must be added a third, the shoaling of the sea bottom, 
which compels ships to anchor far off shore. Such shoals are so 
rare on this dry and almost riverless coast as to be a menace to 
navigation. The steamer Tucapelle, like all west-coast boats, was 
sailing close to the unlighted shore on a very dark night in 
April, 1911, when the usual fog came on. She struck the reef just 
off Camana. Half of her passengers perished in trying to get 
through the tremendous surf that broke over the bar. The most 
practicable scheme for the development of the port would seem to 
be a floating dock and tower anchored out of reach of the surf, 
and connected by cable with a railway on shore. Harbor works 
would be extraordinarily expensive. The valley can support only 
a modest project. 

The relations of Fig. 65, representing the Camana- Vitor re- 
gion, are typical of southern Peru, with one exception. In a few 
valleys the streams are so small that but little water is ever found 
beyond the foot of the mountains, as at Moquegua. In the Chili 
Valley is Arequipa (8,000 feet), right at the foot of the big cones 
of the Maritime Cordillera (see Fig. 6). The green valley floor 
narrows rapidly and cultivation disappears but a few miles below 
the town. Outside the big valleys cultivation is limited to the best 



118 



THE ANDES OF SOUTHERN PERU 



spots along the foot of the Coast Bange, where tiny streams or 
small springs derive water from the zone of clouds and fogs on the 
seaward slopes of the Coast Eange. Here and there are olive 
groves, a vegetable garden, or a narrow alfalfa meadow, watered 



^^MIT3 OF IRRIGABLE LAND 




CMROINATK OF ICR 
LONO 75*30' W.orC. 
L»r. I+' S 



LIMITS OF 
IRRIGABLE LAND 



llRRItATEO LAND 




\^ LACUNA 

N't, ^^ 

— ^^ A 




Fig. 67- — Irrigated and irrigable land 
in the lea Valley of the coastal desert of 
Peru. 



Fig. 6S — The projected canal to con- 
vey water from the Atlantic slope to the 
Pacific slope of the Maritime Cordillera.' 



by uncertain springs that issue below the hollows of the bordering 
mountains. 

In central and northern Peru the coastal region has aspects 
quite different from those about Camana. At some places, for 
example north of Cerro Azul, the main spurs of the Cordillera 
extend down to the shore. There is neither a low Coast Eange 
nor a broad desert pampa. In such places flat land is found only 
on the alluvial fans and deltas. Lima and Callao are typical. 
Fig. 66, compiled from Adams 's reports on the water resources of 

" Figs. 67 and 68 are from Bol. de Minas del Perfl, 1906, No. 37, pp. 82 and 84 
respectively. 



THE COASTAL DESERT 



119 



the coastal region of Peru, shows this distinctive feature of the 
central region. Beyond Salaverry extends the northern region, 
where nearly all the irrigated land is found some distance hack 
from the shore. The farther north we go the more marked is this 



3M. 
IM, 


JAN 


FEB 


MARCH 


APRIL 


MAY 


JUNE 


JULY 


AUG 


SEPT 


OCT, 


NOV 


DEC 
























































Lw,^ 




















k? 


^m 


^fc 



















Fig. 69 — A stream of the intermittent type in the coastal desert of Peru. Depth 
of water in the Puira River at Puira, 1905. (Bol. de Minas del PerQ, 1906, No. 45, p. 2.) 

feature, hecause the coastal belt widens. Catacaos is several miles 
from the sea, and Piura is an interior place. At the extreme north, 
where the rains begin, as at Tumbez, the cultivated land once more 
extends to the coast. 

These three regions contain all the fertile coastal valleys of 
Peru. The larger ones are impressive — with cities, railways, 




Fig. 70 — A stream of the perennial type in the coastal desert of Peru. Depth of 
water in the Chira River at Sullana, 1905. Data from May to September are ap- 
proximate. (Bol. de Minas del Perti, 1906, No. 45, p. 2.) i 

ports, and land in a high state of cultivation. But they are after 
all only a few hundred square miles in extent. They contain less 
than a quarter of the people. The whole Pacific slope from the 
crest of the Cordillera has about 15,000 square miles (38,850 sq. 
km.), and of this only three per cent is irrigated valley land, as 
shown in Fig. 66. Moreover, only a small additional amount may 
be irrigated, perhaps one half of one per cent. Even this amount 



/ 



^ 



120 THE ANDES OF SOUTHERN PERU 

may be added not only by a better use of the water but also by the 
diversion of streams and lakes from the Atlantic to the Pacific. 
Figs. 67 and 68 represent such a project, in wliich it is proposed to 
carry the water of Lake Choclococha through a canal and tunnel 
under the continental divide and so to the head of the lea Valley. 
A little irrigation can be and is carried on by the use of well water, 
but this will never be an important source because of the great 
depth to the ground water, and the fact that it, too, depends ulti- 
mately upon the limited rains. 

The inequality of opportunity in the various valleys of the 
coastal region depends in large part also upon inequalitj' of 
river discharge. This is dependent chiefly upon the sources of the 
streams, whether in snowy peaks of the main Cordillera \yit\i 
fairly constant run-off, or in the western spurs where summer 
rains bring periodic high water. A third type has high water dur- 
ing the time of greatest snow melting, combined with summer 
rains, and to this class belongs the Majes Valley with its sources 
in the snow-cap of Coropuna. The other two types are illustrated 
by the accompanying diagrams for Puira and Chira, the former 
intermittent in flow, the latter fairly constant." 

" The Bolettn de Miiias del Perfl, No. 34, 1905, contnina n graphic representation 
of the rfgime of the Kio Chili at Arequipa for the yeurg 1901-1905. 



72'30' 




15"50'' 



72'30' 



tNe.AND PTG.RYTHE TOPOGRAPHIC ErJOSAV.'MO CO. VVASH.,D. C. 

Edition of iSIS. 



6°20' 



THE "KME PERXjVIAN EXPSDITIOl^: 
BIBAM BINGHAM:. DIRECTOR 
AE^LAC OITADItANGLE 
(Coropumtt 





. \r%.. 



-) 



CHAPTER IX 
CLIMATOLOGY OF THE PERUVIAN ANDES 

CLIMATIC BELTS 

The noble proportions of the Peruvian Andes and their posi- 
tion in tropical latitudes have given them climatic conditions of 
great diversity. Moreover, their great breadth and continuously 
lofty summits have distributed the various climatic types over 
spaces sufficiently ample to affect large and important groups of 
people. When we add to this the fact that the topographic types 
developed on a large scale are distributed at varying elevations, 
and that upon them depend to a large degree the chief character- 
istics of the soil, another great factor in human distribution, we 
are prepared to see that the Peruvian Andes afford some strik- 
ing illustrations of combined climatic and topographic control 
over man. 

The topographic features in their relations to the people have 
been discussed in preceding chapters. We shall now examine the 
corresponding effects of climate. It goes without saying that the 
topographic and climatic controls cannot and need not be kept 
rigidly apart. Yet it seems desirable, for all their natural inter- 
dependence, to give them separate treatment, since the physical 
laws upon which their explanations depend are of course entirely 
distinct. Further, there is an independent group of human re- 
sponses to detailed climatic features that have little or no connec- 
tion with either topography or soil. 

The chief climatic belts of Peru run roughly from north to 
south in the direction of the main features of the topography. Be- 
tween 13° and 18° S., however, the Andes run from northwest to 
southeast, and in short stretches nearly west-east, with the result 
that the climatic belts likewise trend westward, a condition 
well illustrated on the seventy-third meridian. Here are devel- 

131 



122 THE ANDES OF SOUTHERN PERU 

oped important climatic features not found elsewhere in Peru. 
The trade Avinds are greatly modified in direction and effects ; the 
northward-trending valleys, so deep as to be secluded from the 
trades, have floors that are nearly if not quite arid; a restricted 
coastal region enjoys a heavier rainfall ; and the snowline is much 
more strongly canted from west to east than anyivhere else in the 
long belt of mountains from Patagonia to Venezuela. These ex- 
ceptional features depend, however, upon precisely the same phys- 
ical laws as the normal climatic features of the Peruvian Andes. 
They can, therefore, be more easily understood after attention has 
been given to the larger aspects of the climatic problem of which 
they form a part. 

The critical relations of trade winds, lofty mountains, and 
ocean currents that give distinction to Peruvian climate are shown 
in Figs. 71 to 73. From them and Fig. 74 'it is clear that the two 
sides of the Peruvian mountains are in sharp contrast climatically. 
The eastern slopes have almost daily rains, even in the dry season, 
and are clothed with forest. The western leeward slopes are so 
dry that at 8,000 feet even the most drought-resisting grasses 
stop — only low shrubs live below this level, and over large areas 
there is no vegetation whatever. An exception is the Coast 
Eange,(not shown on these small maps, but exhibited in the suc- 
ceeding diagram. These have moderate rains on their seaward 
(westerly) slopes during some years and grass and shrubby 
vegetation grow between the arid coastal terraces below them 
and the parched desert above. The greatest variety of climate is 
enjoyed by the mountain zone. Its deeper valleys and basins de- 
scend to tropical levels ; its higher ranges and peaks are snow-cov- 
ered. Between are the climates of half the world compressed, it 
may be, between 6,000 and 15,000 feet of elevation and with ex- 
tremes only a day's journey apart. 

In the explanation of these contrasts we have to deal with rela- 
tively simple facts and principles ; but the reader who is interested 
chiefly in the human aspects of the region should turn to p. 138 
where the effects of the climate on man are set forth. The 
ascending trades on the eastern slopes pass successively into 



CLIMATOLOGY OF THE PERUVIAN ANDES 



123 




Fig. 71. 



Fio. 72. 



WET j>;^SUB,-iiUMIDl 
COAST K^HIGl/ljmOs| 




(4\ SEMI- 
siJ'XMOUNTAINS, 



■\ PLATEAUS AN DrK - 
■^ ^-BASINSS^ 



FlQ. 73. 



Fio. 74. 



FiQ. 71 — The three chief topographic regions of Peru. 

Fig. 72 — The wind belts of Peru and ocean currents of adjacent waters. 

■ FiQ. 73 — The climatic belts of Peru. 

Fig. 74 — Belts of vegetation in Peru. 



124 THE ANDES OF SOUTHERN PERU 

atmospheric levels of diminishing pressure; hence they expand, 
deriving the required energy for expansion from the heat of 
the air itself. The air thereby cooled has a lower capacity for 
the retention of water vapor, a function of its temperature; 
the colder the air the less water vapor it can take up. As 
long as the actual amount of water vapor in the air is less 
than that which the air can hold, no rain falls. But the cool- 
ing process tends constantly to bring the warm, moist, ascend- 
ing air currents to the limit of their capacity for water vapor 
by diminishing the temperature. Eventually the air is saturated 
and if the capacity diminishes stUl further through diminishing 
temperature some of the water vapor must be condensed from a 
gaseous to a liquid form and be dropped as rain. 

The air currents that rise thousands of feet per day on the 
eastern slopes of the Andes pass again and again through this 
practically continuous process and the eastern aspect of the moun- 
tains is kept rain-soaked the whole year round. For the trades 
here have only the rarest reversals. Generally they blow from the 
east day after day and repeat a fixed or average type of weather 
peculiar to that part of the tropics under their steady domination. 
During the southern summer, when the day-time temperature con- 
trasts between mountains and plains are strongest, the force of 
the trade wind is greatly increased and likewise the rapidity of the 
rain-making processes. Hence there is a distinct seasonal differ- 
ence in the rainfall — what we call, for want of a better name, a 
"wet" and a "dry" season. 

On the western or seaward slopes of the Peruvian Andes the 
trade winds descend, and the process of rain-making is reversed 
to one of rain-taking. The descending air currents are com- 
pressed as they reach lower levels where there are progressively 
higher atmospheric pressures. The energy expended in the proc- 
ess is expressed in the air as heat, whence the descending air gains 
steadily in temperature and capacity for water vapor, and there- 
fore is a drying wind. Thus the leeward, western slopes of the 
mountains receive little rain and the lowlands on that side are 
desert. 



CLIMATOLOGY OF THE PERUVIAN ANDES 



125 



THE CLIMATE OF THE COAST 

A series of narrow but pronounced climatic zones coincide with 
the topographic subdivisions of the western slope of the country 
between the crest of the Maritime Cordillera and the Pacific Ocean. 
This belted arrangement is diagrammatically shown in Fig. 75. 
From the zone of lofty mountains with a well-marked summer 
rainy season descent is made by lower slopes with successively 



ZONE OF 
COASTAL TER- 
RACES 
RAIN ONCE 
IN MANY 
YEARS 


ZONEOFFOG- 
COVEREO MOUN- 
TAINS 

RAINAT INTER- 
VALS OF 5-10 
YEARS 5.C 


00' 


ZONE OF DESERT PLAINS 

RAIN AT INTERVALS OFMANY YEARS 


ZONEOFSTEEP 

VALLEYS 
YEARLY RAINS 


ZONE OF LOFTY MOUNTAINS AND 
PLATEAUS y^<;9'^&_ 

FREQUENT RAINS IN^^^^jJ^-^^O*? 


1?^^^- 


— 


PROFILE OF MAJES VALLEY 


— "' 





Fig. 75 — Topographic and climatic provinces in the coastal region of Peru. The 
broadest division, into the zones of regular annual rains and of irregular rains, occurs 
approximately at 8,000 feet but is locally variable. To the traveler it is always clearly 
defined by the change in architecture, particularly of the house roofs. Those of the 
coast are flat; those of the sierra are pitched to facilitate run off. 



less and less precipitation to the desert strip, where rain is only 
known at irregular intervals of many years ' duration. Beyond lies 
the seaward slope of the Coast Range, more or less constantly 
enveloped in fog and receiving actual rain every few years, and 
below it is the very narrow band of dry coastal terraces. 

The basic cause of the general aridity of the region has already 
been noted ; the peculiar circumstances giving origin to the variety 
in detail can be briefly stated. They depend upon the meteorologic 
and hydrographic features of the adjacent portion of the South 
Pacific Ocean and upon the local topography. 

The lofty Andes interrupt the broad sweep of the southeast 
trades passing over the continent from the Atlantic; and the wind 
circulation of the Peruvian Coast is governed to a great degree 
by the high pressure area of the South Pacific. The prevailing 
winds blow from the south and the southeast, roughly paralleling 
the coast or, as onshore winds, making a small angle with it. 
When the Pacific high pressure area is best developed (during the 
southern winter), the southerly direction of the winds is empha- 



126 



THE ANDES OF SOUTHERN PERU 



F. 











-^ 


<\ 


Air 


2a.m^ 






^v \/^ • 


''Air 4p.m. 


-^ 






- 


Sea 12a.m>^ 
Sea Sa.m^., 


;^ea 4p.m. 











kx 


Air 8a.m. 




■■<-.^ 


N >^ 


^'^ 








~-- 



sized, a condition clearly shown on the Pilot Charts of the South 
Pacific Ocean, issued by the U. S. Hydrographic Office. 

The hydrographic feature of greatest importance is the Hum- 
boldt Current. To its cold waters is largely due the remarkably 
low temperatures of the coast.^ In the latitude of Lima its mean 
JUNE JULY AUG. SEPT. surfacc tcmperature is about 

10° below normal. Lima itself 
has a mean annual tempera- 
ture 4.6° F. below the theo- 
retical value for that latitude, 
(12° S.). An accompanying 
curve shows the low tem- 
perature of Callao during the 
winter months. From mid- 
June to mid-September the 
mean was 61° F., and the 
annual mean is only 65.6° F. 
(18° C). The reduction in 
temperature is accompanied by 
a reduction in the vapor capac- 
ity of the super-incumbent air, 
an effect of which much has 
been made in explanation of 
the west-coast desert. That it is a contributing though not ex- 
clusive factor is demonstrated in Fig. 77. Curve A represents 
the hypothetical change of temperature on a mountainous coast 
with temporary afternoon onshore mnds from a warm sea. 
Curve B represents the change of temperature if the sea be 
cold (actual case of Peru). The more rapid rise of curve B 
to the right of X-X', the line of transition, and its higher eleva- 
tion above its former saturation level, as contrasted with A, 
indicates greater dryness (lower relative humidity). There has 
been precipitation in case A, but at a higher temperature, hence 



Fig. 76 — Temperatures at Callao, Juue- 
September, 1912, from observations taken 
by Captain A. Taylor, of Callao. Air tem- 
peratures are shown by heavy lines; sea 
temperatures by light lines. In view of 
the scant record for comparative land and 
water temperatures along the Peruvian 
coast this record, short as it is, has special 
interest. 



'Hann (Handbook of Climatology, translated by R. Do C. Ward, New York, 1903) 
indicates a contributory cause in the upwelling of cold water along the coa.«t caused 
by the steady westerly drift of the equatorial current. 



CLIMATOLOGY OF THE PERUVIAN ANDES 127 

more water vapor remains in the air after precipitation has 
ceased. Curve B ultimately rises nearly to the level of A, for 
mth less water vapor in the air of case B the temperature rises 
more rapidly (a general law). Moreover, the higher the tem- 
perature the greater the radiation. To summarize, curve A rises 
more slowly than curve B, (1) because of the greater amount 
of water vapor it contains, which must have its temperature 
raised with that of the air, and thus absorbs energy which would 



BELT OF FALLING TEMPERATURES BELT OF RISING TEMPERATURES, 

CLOUD BANKS.HIGH DEW POINT CLEAR SKIES,LOW DEW POINT, 

ANDMODERATEPRECIPITATION AND ARIDITY 
x 




-SATURATION TEMPERATURE- 



jX' SATURATION TEMPERATURE - 

SEASHORE COAST RANGES DESERT 



c. 

JO" 
2b° 
2V 
15' 
JO' 
5' 
0' 



Yia. 77 — To show progressive lowering of saturation temperature in a desert under 
the influence of the mixing process whereby dry and cool air from aloft sinks to lower 
levels thus displacing the warm surface air of the desert. The evaporated moisture of 
the surface air is thus distributed through a great volume of upper air and rain becomes 
increasingly rarer. Applied to deserts in general it shows that the effect of any 
cosmic agent in producing climatic change from moist to dry or dry to moist will 
be disproportionately increased. The shaded areas C and C represent the fog-covered 
slopes of the Coast Range of Peru as shown in Fig. 92. X — X' represents the crest of 
the Coast Range. 

otherwise go to increase the temperature of the air, and (2) be- 
cause its loss of heat by radiation is more rapid on account of its 
higher temperature. We conclude from these principles and de- 
ductions that under the given conditions a cold current intensi- 
fies, but does not cause the aridity of the west-coast desert. 

Curves a and h represent the rise of temperature in two con- 
trasted cases of warm and cold sea with the coastal mountains 
eliminated, so as to simplify the principle applied to A and B. 
The steeper gradient of h also represents the fact that the lower 
the initial temperature the dryer will the air become in passing 
over the warm land. For these two curves the transition line 
X-X.' coincides with the crest of the Coast Eange. It will also be 
seen that curve a is never so far from the saturation level as 



128 



THE ANDES OF SOUTHERN PERU 



9 a.m 



DEC, JAN., 1897-1900 

N 




8 a.m. 




JUNE II- SEPT. 11, 1912 
Noon 




4 p.m. 



Fig. 78 — Wind roses for Callao. The figures for the earlier pe- 
riod (1897-1900) are drawn from data in the Boletfn de la Sociedad 
Geogrfifica de Lima, Vols. 7 and 8, 1898-1900: for the latter period 
data from observations of Captain A. Taylor, of Callao. The diam- 
eter of the circle represents the proportionate number of observations 
when calm was resistered. 




CLIMATOLOGY OF THE PERUVIAN ANDES 



129 



curve b. Hence, unusual atmospheric disturbances would result 
in heavier and more frequent showers. 

Turning now to local factors we find on the west coast a re- 
gional topography that favors a diurnal periodicity of air move- 
ment. The strong slopes of the Cordillera and the Coast Kange 
create up-slope or eastward air gradients by day and opposite 



OCT.-MARCH, 1893- '95 




2 p.m. 




8 a.m 




APRIL-SEPT., 1893- '95 




8 p.m 




FiQ. 79 — Wind roses for Mollendo. The figures are drawn from data in Peruvian 
Meteorology (1892-1895), Annals of the Astronomical Observatory of Harvard College, 
Vol. 39, Pt. 2, Cambridge, Mass., 1906. Observations for an earlier period, Feb. 
1889-March 1890, (Id. Vol. 39, Pt. 1, Cambridge, Mass. 1899) record S. E. wind at 
2 p. m. 97 per cent of the observation time. 



gradients by night. To this circumstance, in combination with 
the low temperature of the ocean water and the direction of the 
prevailing winds, is due the remarkable development of the sea- 
breeze, without exception the most important meteorological fea- 
ture of the Peruvian Coast. Several graphic representations are 
appended to show the dominance of the sea-breeze (see wind roses 



130 



THE ANDES OF SOUTHERN PERU 



for Callao, MoUendo, Arica, and Iquiqxie), but interest in the 
phenomenon is far from being confined to the theoretical. Every- 
where along the coast the virason, as the sea-breeze is called in 
contradistinction to the terral or land-breeze, enters deeply into 
the affairs of human life. According to its strength it aids 
or hinders shipping; sailing boats may enter port on it or it 



7 a.m. 



OCT.-MARCH 

N 




Fig. 80 — Wind roses for the summer and winter seasons of the years 1911-1913. 
The diameter of the circle in each case shows the proportion of calm. Figures are 
drawn from data in the Anuario Meteorologico de Chile, Publications No. 3, (1911), 
6 (1912) and 13 (1913), Santiago, 1912, 1914, 1914. 

may be so violent, as, for example, it commonly is at Pisco, 
that cargo cannot be loaded or unloaded during the afternoon. 
On the nitrate pampa of northern Chile (20° to 25° S.) it not 
infrequently breaks with a roar that heralds its coming an 
hour in advance. In the Majes Valley (12° S.) it blows gustily 
for a half -hour and about noon (often by eleven o'clock) it 
settles down to an uncomfortable gale. For an hour or two 



CLIMATOLOGY OF THE PERUVIAN ANDES 



131 



before the sea-breeze begins the air is hot and stifling, and 
dust clouds hover about the traveler. The maximum tempera- 
ture is attained at this time and not around 2.00 p. m. as is nor- 
mally the case. Yet so boisterous is the noon wind that the laborers 
time their siesta by it, and not by the high temperatures of earlier 

OCT.-MARCH 



7 a.m. 




2 p.m. 




APRIL- SEPT. 
2 p.m. 





Fig. 81 — Wind roses for Iquique for the summer and winter seasons of tlie years 
1911-1913. The diameter of the circle in each ease shows the proportion of calm. 
For source of data see Fig. 80. 

hours. In the afternoon it settles down to a steady, comfortable, 
and dustless wind, and by nightfall the air is once more calm. 

Of highest importance are the effects of the sea-breeze on pre- 
cipitation. The bold heights of the Coast Eange force the nearly 
or quite saturated air of the sea-wind to rise abruptly several 
thousand feet, and the adiabatic cooling creates fog, cloud, and 
even rain on the seaward slope of the mountains. The actual form 
and amount of precipitation both here and in the interior region 
vary greatly, according to local conditions and to season and also 
from year to year. The coast changes height and contour from 



132 



THE ANDES OF SOUTHERN PERU 



place to place. At Arica the low coastal chain of northern Chile 
terminates at the Morro de Arica. Thence northward is a stretch 
of open coast, with almost no rainfall and little fog. But in the 
stretch of coast between Mollendo and the Majes Valley a coastal 
range again becomes prominent. Fog enshrouds the hills almost 
daily and practically every year there is rain somewhere along 
their western aspect. 

During the southern winter the cloud bank of the coast is best 
developed and precipitation is greatest. At Lima, for instance, 



EASrERLy WIHDS FEEBLE 




RAINV SEASON 

SEA BREEZE 



Fig. 82 — The wet and dry seasons of 
the Coast Range and the Cordillera are 
complementary in time. The " wet " 
season of the former occurs during the 
southern winter; the cloud bank on the 
seaward slopes of the hills is best devel- 
oped at that time and actual rains may 
occur. 



EASTEm WINOSATHIGHEirVATinH 



DRY SEASON 

SEA BREEZE 



!S^ 



htImboTbt current ^ 



RAINY SEASON ^ 

MAH'TIMtCfRSIOEHA 



FlQ. 83 — During the southern summer 
the seaward slopes of the Coast Range are 
comparatively clear of fog. Afternoon 
cloudiness is characteristic of the desert 
and increases eastward (compare Fig. 
86), the influence of the strong sea winds 
as well as that of the trades (compare 
Fig. 93B) being felt on the lower slopes 
of the Maritime Cordillera. 



the clear skies of March and April begin to be clouded in May, and 
the cloudiness grows until, from late June to September, the sun 
is invisible for weeks at a time. This is the period of the garua 
(mist) or the "tiempo de lomas," the "season of the hills," when 
the moisture clothes them with verdure and calls thither the herds 
of the coast valleys. 

During the southern summer on account of the greater relative 
difference between the temperatures of land and water, the sea- 
breeze attains its maximum strength. It then accomplishes its 
greatest work in the desert. On the pampa of La Joya, for exam- 
ple, the sand dunes move most rapidly in the summer. According 
to the Peruvian Meteorological Records of the Harvard Astronom- 
ical Observatory the average movement of the dunes from April 
to September, 1900, was 1.4 inches per day, while during the sum- 
mer months of the same year it was 2.7 inches. In close agree- 
ment are the figures for the wind force, the record for which also 



f 



CLIMATOLOGY OF THE PERUVIAN ANDES 



133 



Jvme, July 




The relative humidity 

Dec, Jan. 
9 a.m. 





3 p.m. 




shows that 95 per cent of the winds with strength over 10 miles per 
hour blew from a southerly direction. Yet during this season the 
coast is generally clearest of fog and cloud. The explanation ap- 
pears to lie in the exceedingly delicate nature of the adjustments 
between the various rain-making forces 
of the air from the sea is al- 
ways high, but on the im- 
mediate coast is slightly less 
so in summer than in win- 
ter. Thus in Mollendo the 
relative humidity during the 
mnter of 1895 was 81 per 
cent; during the summer 78 
per cent. Moreover, the 
temperature of the Coast 
Eange is considerably higher 
in summer than in winter, 
and there is a tendency to 
reevaporation of any mois- 
ture that may be blown 
against it. The immediate 
shore, indeed, may still be 
cloudy as is the case at Cal- 
lao, which actually has its 
cloudiest season in the sum- 
mer, but the hills are com- 
paratively clear. In conse- 
quence the sea-air passes 
over into the desert, where 
the relative increase in tem- 
perature has not been so 
great (compare Mollendo and La Joya in the curve for mean 
monthly temperature), with much higher vapor content than in 
winter. The relative humidity for the winter season at La Joya, 
1895, was 42.5 per cent; for the summer season 57 per cent. The 
influence of the great barrier of the Maritime Cordillera, aided 




9p.in. 




v^;^X' i 



'^'^ Overcast 



Scale o£ CloTidiness 
CZIClear 11^0-2.5 £232.5-7.5 ^9.5-10 

Fig. S4 — Cloudiness at Callao. Figures 
are drawn from data in the Boletin de la 
Sociedad Geografioa de Lima, Vols. 7 and 8, 
1898-1900. They represent the conditions at 
three observation hours during the summers 
(Dee., Jan.) of 1897-1898, 1898-1899, 1899- 
1900 and the winters (June, July) of 1898 and 
1899. 



13i 



THE ANDES OF SOUTHERN PERU 



doubtless by convectional rising, causes ascent of the compara- 
tively humid air and the formation of cloud. Farther eastward, 
as the topographic influence is more strongly felt, the cloudiness 

1894 1895 




Fig. 85 — Temperature curves for Mollendo (solid lines) and La Joya (broken 
lines) April, 1894, to December, 1895, dra\vn from data in Peruvian Meteorology, 1892- 
1895, Annals of the Astronomical Observatory of Harvard College, Vol. 49, Pt. 2, 
Cambridge, Mass., 1908. Tlie approximation of the two curves of maximum tempera- 
ture during the winter months contrasts with the well-maintained difference in minimum 
temperatures throughout the year. 

increases until on the border zone, about 8,000 feet in elevation, it 
may thicken to actual rain. Data have been selected to demon- 
strate this eastern gradation of meteorological phenomena. 











1892 


















1893 


















1894 






















1895 
















A 


M 


J 


J 


A 


s 





N 


I) 


J 


F 


M 


A 


M 


J 


J AS 


o 


N 


D 


J 


F 


M 


A 


M 


J 


J 


A 


s 


o 


N 


D 


J 


F 


M 


A 


M{J |J|A 


s 





N 


D 














































































1 1 
















WI^ 


I 


SB 




SUMMER 




\MI> 


ITEI 


i 




3lj 


M 


HER 




W 


nt: 


:r 




SL 


MMEr 






WINTER 








10 

g 


























































A, 


































8 
7 










-1 




^ 






















/\ 






















V 


-> 






































A 






\ 


















^ 


y 




















/ 








^ 
















/ 




-- 
















/ 










\ 














/ 








^ 
















' 










,Mol 


cr 


li( 
























6 






J 












1 












' 










\ 












/ 












\. 










/ 












y 








/ 
























y 














N 








/ 


















\ 
























/ 


















\ 






r 


















'^ 
























s 








HI 








3 


2 
1 





















v. 


*v 


^ , 






















\l 














L 


a Joi 


A 




































„J 


,> 






■". 




^ 












/ 






•^ 


'^J 
































^ 




>. 




^ 


^ 


'"" 




^ 


J 


■- 


■ 
















'■ — 


n- 


- 


■' 


_ 












^ 




— 


'^ 


-- 


^ 






_ 




^ 


^ 


.•^--• 




'' 








Fig. 86 — Mean monthly cloudiness for Mollendo (solid line) and La Joya (broken 
line) from April, 1892, to December, 1895. Mollendo, 80 feet elevation, has the maximum 
winter cloudiness characteristic of the seaward slope of the Coast Range (compare 
Fig. 82) while the desert station of La Joya, 4,140 feet elevation, has typical summer 
cloudiness (compare Fig. 83). Figures are drawn from data in Peruvian Meteorology, 
1892-1895, Annals of the Astronomical Observatory of Harvard College, Vol. 49, Pt. 2, 
Cambridge, Mass., 1908. 

At La Joya, a station on the desert northeast of Mollendo at 
an elevation of 4,140 feet, cloudiness is always slight, but it in- 

Caraveli, at an altitude of 



creases markedly during the summer. 



CLIMATOLOGY OF THE PERUVIAN ANDES 



135 



5,635 feet/ and near the eastern border of the pampa, exhibits a 
tendency toward the climatic characteristics of the adjacent zone. 
Data for a camp station out on the pampa a few leagues from 
the town, were collected by Mr. J. P. Little of the staff of the 



8 a.m. 




2 p.m. 




8 p.m, 




Fig. 87 — Wind roses for La Joya for the period April, 1892, to December, 1895. 
Compare the strong afternoon indraught from the south with the same plienomenon 
at Mollendo, Fig. 79. Figures drawn from data in Peruvian Meteorology, 1892-1895, 
Annals of the Astronomical Observatory of Harvard College, Vol. 39, Pt. 2, Cambridge, 
Mass., 1906. 

Peruvian Expedition of 1912-13. They relate to the period 
January to March, 1913. Wind roses for these months show the 
characteristic light northwesterly winds of the early morning 
hours, in sharp contrast with the strong south and southwesterly 
indraught of the afternoon. The daily march of cloudiness is 
closely coordinated. Quotations from Mr. Little's field notes fol- 
low: 

"In the morning there is seldom any noticeable wind. A 
breeze starts at 10 a. m., generally about 180° (i. e. due south), 
increases to 2 or 3 velocity at noon, having veered some 25° to the 
southwest. It reaches a maximum velocity of 3 to 4 at about 4.00 
p. M., now coming about 225° (i. e. southwest). By 6 p. m. the wind 



° This is the elevation obtained by the .Peruvian Expedition. Eaimondi's figure 
(1,832 m.) is higher. 



136 



THE ANDES OF SOUTHERN PERU 



has died down considerably and the evenings are entirely free 
from it. The wind action is about the same every day. It is not 
a cold wind and, except with the fog, not a damp one, for I have 
not worn a coat in it for three weeks. It has a free unobstructed 
sweep across fairly level pampas. . . . At an interval of every 
three or four days a dense fog sweeps up from the southwest, 
dense enough for one to be easily lost in it. It seldom makes even 




FlQ. 88 — Wind roses for a station on the eastern border of the Coast Desert near 
Caraveli during the summer (January to March) of 1913. Compare with I'ig. 87. 
The diameter of the circle in eacli case represents tlie proportion of ealm. Note the 
characteristic morning calm. 

a sprinkle of rain, but carries hea\^ moisture and will wet a man 
on horseback in 10 minutes. It starts about 3 p. m. and clears 
away by 8.00 p. m. . . . During January, rain fell in camp twice 
on successive days, starting at 3.00 p. m. and ceasing at 8.00 p. m. 
It was merely a light, steady rain, more the outcome of a dense 
fog than a rain-cloud of quick approach. In Caraveli, itself, I am 
told that it rains off and on all during the month in short, light 
showers." This record is dated early in February and, in later 
notes, that month and March are recorded rainless. 

Chosica (elevation 6,600 feet), one of the meteorological sta- 
tions of the Harvard Astronomical Observatory, is still nearer the 



CLIMATOLOGY OF THE PERUVIAN ANDES 



137 



border. It also lies farther north, approximately in the latitude 
of Lima, and this in part may help to expMn the greater cloudi- 
ness and rainfall. The rainfall for the year 1889-1890 was 6.14 
inches, of which 3.94 fell in February. During the winter months 
when the principal wind observations were taken, over 90 per cent 
showed noon winds from a southerly direction while in the early 



6.30-7 a.m. 




11-12 a.m. 




6 p.m. 




Cloudiness 

lilKil 2.5-7.5 



Completely 
Overcast 



IHZl Clear 1123 0-2.5 iffl 2.5-7.5 11117.6-10 

Fig. 89 — Cloudiness at tlie desert station of Fig. S8 (near Caraveli), for the 
summer (January to Mareli) of 1913. 

morning northerly winds were frequent. It is also noteworthy 
that the "directions of the upper currents of the atmosphere as 
•recorded by the motion of the clouds was generally between N. and 
E." Plainly we are in the border region where climatic influences 
are carried over from the plateau and combine their effects with 
those from Pacific sources. Arequipa, farther south, and at an 
altitude of 7,550 feet, resembles Chosica. For the years 1892 to 
1895 its mean rainfall was 5.4 inches. 

Besides the seasonal variations of precipitation there are 
longer periodic variations that are of critical importance on the 
Coast Eange. At times of rather regular recurrence, rains that 
are heavy and general fall there. Every six or eight years is said 
to be a period of rain, but the rains are also said to occur some- 
times at intervals of four years or ten years. The regularity is 
only approximate. The years of heaviest rain are commonly as- 
sociated with an unusual frequency of winds from the north, and 
an abnormal development of the Avarm current. El Nino, from the 



138 



THE ANDES OF SOUTHERN PERU 



18S9 
J A S O N D J 



1890 
F M A M J 



w 


NT 


SR 






1 1 

SUMMER 








w 


NT 


SR 
















































<f^ 


"*\ 
























/ 


f 


A 


\ 


\ 




















\,' 


' / 


1 


\ 


\ 
























/ 


1 




\ 


\ 


\ 


















L/ 


/ 






\ 


\ 


\ 














/ 






( 








\ 


\ 


'. 










..'■ 


/ 














\ 


V 


\ 


r7p; 


mr; 


•■^ 


^ 


y 


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D 


iur 


MX\\ 


nca 


"\ 




f 


















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t 


























1^..,^ 


•\^ 


^"^ 


-^ 



Gulf of Guayaquil. Such was the case in the phenomenally rainy 

year of 1891. The connection is obscure, but undoubtedly exists. 

The effects of the heavy rains are amazing and appear the 

more so because of the extreme aridity of the country east of 

them. During the winter 
the desert traveler finds the 
air temperature rising to 
uncomfortable levels. Vege- 
tation of any sort may be 
completely lacking. As he 
approaches the leeward 
slope of the Coast Eange, a 
cloud mantle full of refresh- 
ing promise may be seen 
just peeping over the crest 
(Fig. 91). Long, slender 
cloud filaments project east- 
ward over the margin of the 
desert. They are traveling 
rapidly but they never ad- 
vance far over the hot 
wastes, for their eastern 
margins are constantly un- 
dergoing evaporation. At times the top of the cloud bank rises 
well above the crest of the Coast Eange, and it seems to the man 
from the temperate zone as if a great thunderstorm were rising in 
the west. But for all their menace of wind and rain the clouds 
never get beyond the desert outposts. In the summer season the 
aspect changes, the heavy yellow sl\y of the desert displaces the 
murk of the coastal mountains and the bordering sea. 

It is an age-old strife renewed every year and limited to a nar- 
row field of action, wonderfully easy to observe. We saw it in its 
most striking form at the end of the winter season in October, 
1911, and for more than a day watched the dnrk clouds rise omi- 
nously only to melt into nothing where the desert holds sway. At 
night we camped beside a scum-coated pool of alkali water no 



ScqIo of 
Cloudmoss 

10 
9 
8 
7 
6 

e 

i 
S 
2 
I 



Fig. 00 — Cloudiness at Cliosica, July, 1889, 
to September, 1890. Cliosica, a station on 
the Oroya railroad east of Lima, is situated 
on the border region between the desert zone 
of the coast and the mountain zone of yearly 
rains. The minimum cloudiness recorded about 
11 a. m. is shown by a broken line; the maxi- 
mum cloudiness, about 7 p. m., by a dotted 
line, and the mean for the 24 hours by a heavy 
solid line. The curves are drawn from data 
in Peruvian Mcteorologj', 1889-1890, Annals 
of the Astronomical Observatory of Harvard 
College, Vol. 39, Pt. 1, Cambridge, Mass., 1899. 



CLIMATOLOGY OF THE PERUVIAN ANDES 139 

larger than a wash basin. It lay in a valley that headed in the 
Coast Eange, and carried do^vn into the desert a mere trickle that 
seeped through the gravels of the valley floor. A little below the 
pool the valley cuts through a mass of granite and becomes a steep- 
walled gorge. The bottom is clogged with waste, here boulders, 
there masses of both coarse and fine alluvium. The water in the 
valley was quite incapable of accomplishing any work except that 
associated with solution and seepage, and we saw it in the wet 
season of an unusually wet year. Clearly there has been a diminu- 
tion in the Avater supply. But time prevented us from explor- 
ing this particular valley to its head, to see if the reduction 
were due to a change of climate, or only to capture of the 
head- waters by the vigorous rain-fed streams that enjoy a favora- 
ble position on the wet seaward slopes and that are extending 
their watershed aggressively toward the east at the expense of 
their feeble competitors in the dry belt. 

An early morning start enabled me to witness the whole series 
of changes between the clear night and the murky day, and to pass 
in twelve hours from the dry desert belt through the wet belt, and 
emerge again into the sunlit terraces at the western foot of the 
Coast Eange. Two hours before daylight a fog descended from 
the hills and the going seemed to be curiously heavy for the beasts. 
At daybreak my astonishment was great to find that it was due 
to the distinctly moist sand. We were still in the desert. There 
was not a sign of a bush or a blade of grass. Still, the surface 
layer, from a half inch to an inch thick, was really wet. The fog 
that overhung the trail lifted just before sunrise, and at the first 
touch of the sun melted away as swiftly as it had come. With it 
went the surface moisture and an hour after sunrise the dust was 
once more rising in clouds around us. 

We had no more than broken camp that morning when a 
merchant with a pack-train passed us, and shouted above the 
bells of the leading animals that we ought to hurry or we should 
get caught in the rain at the pass. My guide, who, like many of 
his kind, had never before been over the route he pretended to 
know, asked him in heaven's name what drink in distant Camana 



140 THE ANDES OF SOUTHERN PERU 

whence he had come produced such astonishing effects as to make 
a man talk about rain in a parched desert. We all fell to laugh- 
ing and at our banter the stranger stopped his pack-train and 
earnestly urged us to hurry, for, he said, the rains beyond the pass 
were exceptionally heavy this year. We rode on in a doubtful 
state of mind. I had heard about the rains, but I could not be- 
lieve that they fell in real showers ! 

About noon the cloud bank darkened and overhung the border 
of the desert. Still the sky above us was clear. Then happened 
what I can yet scarcely believe. We rode into the head of a tiny 
valley that had cut right across the coast chain. A wisp of cloud, 
an outlier of the main bank, lay directly ahead of us. There 
were grass and bushes not a half-mile below the bare dry spot on 
which we stood. We were riding down toward them when of a 
sudden the wind freshened and the cloud wisp enveloped us, shut- 
ting out the view, and ten minutes later the moisture had gath- 
ered in little beads on the manes of our beasts and the trail be- 
came slippery. In a half-hour it was raining and in an hour we 
were in the midst of a heavy downpour. We stopped and pas- 
tured our famished beasts in luxuriant clover. While they gorged 
themselves a herd of cattle drifted along, and a startled band of 
burros that suddenly confronted our beasts scampered out of sight 
in the hea^^ mist. Later we passed a herdsman's hut and long 
before we reached him he shouted to us to alter our course, for 
just ahead the old trail was wet and treacherous at this time 
of year. The warning came too late. Several of our beasts lost 
their footing and half rolled, half slid, down hill. One turned com- 
pletely over, pack and all, and lay in the soft mud calmly taking 
advantage of the delay to pluck a few additional mouthfuls of 
grass. We were glad to reach firmer ground on the other side of 
the valley. 

The herdsmen were a hospitable lot. They had come from 
Camana and rarely saw travelers. Their single-roomed hut was 
mired so deeply that one found it hard to decide whether to take 
shelter from the rain inside or escape the mud by standing in the 
rain outside. They made a little so-called cheese, rounded up and 



CLIMATOLOGY OF THE PERUVIAN ANDES 141 

counted the cattle on clear days, drove them to the springs from 
time to time, and talked incessantly of the wretched rains in the 
hills and the delights of dry Camana down on the coast. We could 
not believe that only some hours' traveling separated two locali- 
ties so wholly unlike. 

The heavy showers and luxuriant pastures of the wet years 
and the light local rains of the dry years endow the Coast Eange 
with many peculiar geographic qualities. The heavy rains pro- 
vide the desert people at the foot of the mountains such a wealth 
of pasture for their burdensome stock as many oases dwellers 
possess only in their dreams. From near and far cattle are driven 
to the wet hill meadows. Some are even brought in from distant 
valleys by sea, yet only a very small part of the rich pastures can 
be used. It is safe to say that they could comfortably support ten 
times the number of cattle, mules, and burros that actually graze 
upon them. The grass would be cut for export if the weather 
were not so continually wet and if there were not so great a mix- 
ture of weeds, flowers, and shrubs. 

Then come the dry years. The surplus stock is sold, and what 
remains is always maintained at great expense. In 1907 I saw 
stock grazing in a small patch of dried vegetation back of Mol- 
lendo, although they had to be driven several miles to water. They 
looked as if they were surviving with the greatest difficulty and 
their restless search for pasture was like the search of a desper- 
ate hunter of game. In 1911 the same tract was quite devoid of 
grass, and except for the contour-like trails that completely cov- 
ered the hills no one would even guess that this had formerly been 
a cattle range. The same year, but five months later, a carpet 
of grass, bathed in heavy mist, covered the soil ; a trickle of water 
had collected in pools on the valley floor; several happy families 
from the town had laid out a prosperous-looking garden; there 
were romping children who showed me where to pick up the trail 
to the port; on every hand was life and activity because the rains 
had returned bringing plenty in their train. I asked a native how 
often he was prosperous. 

"Segun el temporal y la Providencia" (according to the 



14-2 THE ANDES OF SOUTHERN PERU 

weather and to Providence), he replied, as he pointed significantly 
to the pretty green hills crowned with gray mist. 

It, therefore, seems fortunate that the Coast Eange is so placed 
as to intercept and concentrate a part of the moisture that the sea- 
winds carry, and doubly fortunate that its location is but a few 
miles from the coast, thereby giving temporary relief to the rela- 
tively crowded people of the lower irrigated valleys and the towns. 
The wet years formerly developed a crop of prospectors. Pack 
animals are cheaper when there is good pasture and they are also 
easier to maintain. So when the rains came the hopeful pick-and- 
shovel amateurs began to emigrate .from the to-wns to search for 
ore among the discolored bands of rock intruded into the granite 
masses of the coastal hills. Plowever, the most likely spots have 
been so thoroughly and so unsuccessfully prospected for many 
years that there is no longer any interest in the "mines." 

Transportation rates are still most intimately related to the 
rains. My guide had two prices — a high price if I proposed to 
enter a to^vn at night and thus require him to buy expensive 
forage ; a low price if I camped in the hills and reached the town 
in time for him to return to the hills with his animals. Inquiry 
showed that this was the regular custom. I also learned that in 
packing goods from one part of the coast to another forage must 
be carried in dry years or the beasts required to do without. 
In wet years by a very slight detour the packer has his beasts in 
good pasture that is free for all. The merchant who dispatches 
the goods may find his charges nearly doubled in extremely dry 
years. Goods are more expensive and there is a decreased con- 
sumption. The effects of the rains are thus transmitted from one 
to another, until at last nearly all the members of a community 
are bearing a share of the burdens imposed by drought. As al- 
ways there are a few who prosper in spite of the ill wind. If the 
pastures fail, live stock must be sold and the dealers ship south 
to the nitrate ports or north to the large coast towns of Peru, 
where there is always a demand. Their business is most active 
when it is dry or rather at the beginning of the dry period. Also 
if transport by land routes becomes too expensive the small trad- 



CLIMATOLOGY OF THE PERUVIAN ANDES 143 

ers turn to the sea routes and tlie carriers have an increased busi- 
ness. But so far as I have been able to learn, dry years favor 
only a few scattered individuals. 

To the traveler on the west coast it is a source of constant sur- 
prise that the sky is so often overcast and the ports hidden by fog, 
while on every hand there are clear evidences of extreme aridity. 
Likewise it is often inquired why the sunsets there should be often 
so superlatively beautiful during the winter months when the 
coast is fog bound. Why a desert when the air is so humid? Why 
striking sunsets when so many of the days are marked by dull 
skies'? As we have seen in the first part of this chapter, the big 
desert tracts lie east of the Coast Eange, and there, excepting 
slight summer cloudiness, cloudless skies are the rule. The des- 
ert just back of the coast is in many parts of Peru only a narrow 
fringe of dry marine terraces quite unlike the real desert in type 
of weather and in resources. The fog bank overhanging it 
forms over the Humboldt Current which lies off shore; it drifts 
landward with the onshore wind ; it forms over the upwelling cold 
water between the current and the shore; it gathers on the sea- 
ward slopes of the coastal hills as the inflowing air ascends them 
in its journey eastward. Sometimes it lies on the surface of the 
land and the water; more frequently it is some distance above 
them. On many parts of the coast its characteristic position is 
from 2,000 to 4,000 feet above sea level, descending at night nearly 
or quite to the surface, ascending by day and sometimes all but 
disappearing except as rain-clouds on the hills.^ Upon the local 
behavior of the fog bank depends in large measure the local cli- 
mate. A general description of the coastal climate will have many 



" According to Ward's observations the base of the cloud belt averages between 
2,000 and 3,000 feet above sea level (Climatic Notes Made During a Voyage Around 
South America, Journ. of School Geogr., Vol. 2, 1898). On the south Peruvian coast, 
specifically at Mollendo, Middendorf found the cloud belt beginning about 1,000 feet 
and extending upwards to elevations of 3,000 to 4,000 feet. At Lima the clouds descend 
to lower levels (El Clima de Lima, Bol. Soc. Geogr. de Lima, Vol. 15, 1904). In 
the third edition of his Siid- und Mittelamerika (Leipzig and Vienna, 1914) Sievers 
says that at Lima in the winter the cloud on the coast does not exceed an elevation 
of 450 m. (1,500 feet) while on the hills it lies at elevations between 300 and 700 m. 
(1,000 and 2,300 feet). 



lU THE ANDES OF SOUTHERN PERU 

exceptions. The physical principles involved are, however, the 
same everywhere. I take for discussion therefore the case illus- 
trated by Fig. 92, since this also displays with reasonable fidelity 
the conditions along that part of the Peruvian coast between 
Camana and MoUendo Avhich lies in the field of work of the Yale 
Peruvian Expedition of 1911. 

Three typical positions of the fog bank are shown in the figure, 
and a fourth — that in which the bank extends indefinitely west- 
ward — may be supplied by the imagination. 

If the cloud bank be limited to C only the early morning hours 
at the port are cloudy. If it extend to B the sun is obscured until 
midday. If it reach as far west as A only a few late afternoon 
hours are sunny. Once in a while there is a sudden splash of rain 
— a few drops which astonish the traveler who looks out upon a 
parched landscape. The smaller drops are evaporated before 
reaching the earth. In spite of the ever-present threat of rain the 
coast is extremely arid. Though the vegetation appears to be 
dried and burned up, the air is humid and for months the sky may 
be overcast most of the time. So nicely are the rain-making con- 
ditions balanced that if one of our ordinary low-pressure areas, 
or so-called cyclonic storms, from the temperate zone Avere set in 
motion along the foot of the mountains, the resulting deluge would 
immediately lay the coast in ruins. The cane-thatched, mud- 
walled huts and houses would crumble in the hea^^ rain like a 
child 's sand pile before a rising sea ; the alluvial valley land would 
be coated with infertile gravel; and mighty rivers of sand, now 
delicately poised on arid slopes, would inundate large tracts of 
fertile soil. 

If the fog and cloud bank extend westward indefinitely, the en- 
tire day may be overcast or the sun appear for a few moments 
only through occasional rifts. Generally, also, it will make an ap- 
pearance just before sunset, its red disk completely filling the nar- 
row space between the under surface of the clouds and the water. 
I have repeatedly seen the ship's passengers and even the crew 
leave the dinner table and collect in Avondering groups about the 
port-holes and doorways the better to see the marvelous play of 




Fig. 91. 



ZONE OF COASTAL TERRACES 

DRV UNDERNEATH FOG-BANK 
S-, FOG-BANK BETWEEN 2,000 AND 4niii'>ur 

PORT 



ZONE OF SUBDUED COASTAL MOUNTAINS 

WET SEAWARD ASPECT DRV LANDWARD ASPECT 



DESERT ZONE 





::T,yPES OF STREAM PROFILES 



Fig. 92. 

Fig. 91 — Looking down the canyon of the Majes River to the edge of the cloud 
bank formed against the Coast Range back of Caniana. 

Fig. 92 — Topographic and climatic cross-section to show the varying positions of 
the cloud bank on the coast of Peru, the dry terrace region, and the types of stream 
profiles in the various belts. 



CLIMATOLOGY OF THE PERUVIAN ANDES 145 

colors between sky and sea. It is impossible not to be profoundly 
moved by so majestic a scene. A long resplendent path of light 
upon the water is reflected in the clouds. Each cloud margin is 
tinged with red and, as the sun sinks, the long parallel bands of 
light are shortened westward, changing in color as they go, until 
at last the full glory of the sunset is concentrated in a blazing arc 
of reds, yellows, and purples, that to most people quite atones for 
the dull gray day and its humid air. 

At times the clouds are broken up by the winds and scattered 
helter-skelter through the west. A few of them may stray into 
the path of the sun temporarily to hide it and to reflect its pri- 
mary colors when the sun reappears. From the main cloud masses 
there reach out slender wind-blown streamers, each one delicately 
lighted as the sun's rays filter through its minute water particles. 
Many streamers are visible for only a short distance, but when 
the sun catches them their filmy invisible fingers become delicate 
bands of light, some of which rapidly grow out almost to the dome 
of the sky. Slowly they retreat and again disappear as the rays 
of the sun are gradually shut off by the upturning curve of the 
earth. 

The unequal distribution of precipitation in the climatic zones 
of western Peru has important hydrographic consequences. These 
will now be considered. In the preceding figure four types of 
stream profiles are displayed and each has its particular relation 
to the cloud bank. Stream 1 is formed wholly upon the coastal 
terraces beneath the cloud bank. It came into existence only 
after the uplift of the earth 's crust that brought the wave-cut plat- 
forms above sea level. It is extremely youthful and on account 
first of the small seepage at its headquarters — it is elsewhere 
wholly without a tributary water supply — and, second, of the re- 
sistant granite that occurs along this part of the coast, it has very 
steep and irregular walls and an ungraded floor. Many of these 
"quebradas" are difficult to cross. A few of them have fences 
built across their floors to prevent the escape of cattle and burros 
that wander down from the grassy hills into the desert zone. 
Others are partitioned oif into corrals by stone fences, the steep 



146 THE ANDES OF SOUTHERN PERU 

walls of the gorge preventing the escape of the cattle. To these 
are driven the market cattle, or mules and burros that are re- 
quired for relays along the shore trail. 

Stream 2 heads in the belt of rains. Furthermore it is a much 
older stream than 1, since it dates back to the time when the Coast 
Eange was first formed. It has ample tributary slopes and a large 
number of small valleys. A trickle of water flows down to become 
lost in the alluvium of the lower part of the valley or to reappear 
in scattered springs. Where springs and seepage occur together, 
an olive grove or a garden marks the spot, a corral or two and a 
mud or stone or reed hut is near by, and there is a tiny oasis. 
Some of these dots of verdure become so dry during a prolonged 
drought that the people, long-established, move away. To others 
the people return periodically. Still others support permanent 
settlements. 

Stream 3 has still greater age. Its only competitors are the 
feeble, almost negligible, streams that at long intervals flow east 
toward the dry zone. Hence it has cut back until it now heads in 
the desert. Its widely branched tributaries gather moisture from 
large tracts. There is running water in the valley floor even down 
in the terrace zone. At least there are many dependable springs 
and the permanent homes that they always encourage. A valley 
of this type is always marked by a well-defined trail that leads 
from settlement to settlement and eastward over the "pass" to 
the desert and the Andean towns. 

Stream 4 is a so-called "antecedent" stream. It existed be- 
fore the Coast Eange was uplifted and cut its channel do^^^lward 
as the mountains rose in its path. The stretch where it crosses 
the mountains may be a canyon with a narrow, rocky, and unculti- 
vable floor, so that the valley trails rise to a pass like that at the 
head of stream 3, and descend again to the settlements at the 
mouth of 4. There is in this last type an abundance of water, for 
the sources of the stream are in the zone of pennanent snoAvs and 
frequent winter rains of the lofty Cordillera of the Andes. The 
settlements along this stream are continuous, except where shut- 
ins occur — narrow, rocky defiles caused by more resistant rock 



CLIMATOLOGY OF THE PERUVIAN ANDES 147 

masses in the path of the stream. Here and there are villages. 
The streams have fish. When the water rises the river may be 
unfordable and people on opposite sides must resort to boats or 
rafts." 

EASTERN BOEDER CLIMATES 

On windward mountain slopes there is always a belt of maxi- 
mum precipitation whose elevation and width vary with the 
strength of the wind, with the temperature, and with the topog- 
raphy. A strong and constant wind will produce a much more 
marked concentration of the rainfall. The belt is at a low eleva- 
tion in high latitudes and at a high elevation in low latitudes, with 
many irregularities of position dependent upon the local and espe- 
cially the minimum winter temperature. The topographic con- 
trols are important, since the rain-compelling elevation may scat- 
ter widely the localities of maximum precipitation or concentrate 
them within extremely narrow limits. The human effects of these 
climatic conditions are manifold. "Wherever the heaviest rains 
are, there, too, as a rule, are the densest forests and often the 
most valuable kinds of trees. If the general climate be favorable 
and the region lie near dense and advanced populations, exploita- 
tion of the forest and progress of the people will go hand in hand. 
If the region be remote and some or all of the people in a primi- 
tive state, the forest may hinder communication and retard devel- 
opment, especially if it lie in a hot zone where the natural growth 
of population is slow. . . . These are some of the considerations 
we shall keep in mind while investigating the climate of the east- 
ern border of the Peruvian Andes. 

The belt of maximum precipitation on the eastern border of 
the Andean Cordillera in Peru lies between 4,000 and 10,000 feet. 
Judging by the temporary records of the expedition and especially 

' In most of the coast towns the ford or ferry is an important institution and the 
cMmbadores or haleadores as they are called are expert at their trade : they know 
the regime of the rivers to a nicety. Several settlements owe their origin to the 
exigencies of transportation, permanent and periodic; thus before the development of 
its irrigation system CamanS, according to General Miller (Memoirs, London, 1829, 
Vol. 2, p. 27), was a hamlet of some 30 people who gained their livelihood through 
ferrying freight and passengers across the Maje3 River. 



/ 



148 



THE ANDES OF SOUTHERN PERU 



by the types of forest growth, the heaviest rains occur around 
8,000 feet. It is between these elevations that the densest part 
of the Peruvian montana (forest) is found. The cold timber line 
is at 10,500 feet with exceptional extensions of a few species to 



ZONEOFLIGHT RAIN AND LOCAL SNOW ZONE OF MAXIMUM RAINFALL ZONE OFMODERATE RAINFALL 



DRY AND WET SEASONS SHARPLY 
MARKED AND EQUAL IN LENGTH 



iONE WELL-MARKED SHORTDRY 
iSEASON 



; ONE WELL-MARKED LONG DRY 
i SEASON 




Fig. 93A — Cloud types and rainfall belts on the eastern border of the Peruvian Andes 
in the dry season, southern winter. The zone of maximum rainfall extends approxi- 
mately from 4,000 to 10,000 feet elevation. 

12,500 feet. In basins or deep secluded valleys near the moun- 
tain border, a dry timber line occurs at 3,000 feet with many varia- 
tions in elevation due to the variable declivity and exposure of the 
slopes and degree of seclusion of the valleys. Elsewhere, the 



TRADES FEEBLER, -LOCAL INFLU- 
ENCES STRONG 



TRADES REINFORCED BY STRONG UP-; 

VALLEY WINDS BY DAY AND NEUTRAL-j 

IZED BY MODERATE DOWN-VALLEvi 

INDSBYNIGHT 



NORMAL TRADES 




Fig. 93B — Cloud types and rainfall belts on the eastern border of the Peruvian 
Andes in the wet season, southern summer. 

mountain forest passes without a break into the plains forest with 
change in type but with little change in density. The procumbent 
and suppressed trees of the cold timber line in regions of hea^y 
winter snows are here absent, for the snows rarely reach below 
14,000 feet and even at that elevation they are only light and tem- 
porary. The line of perpetual snow is at 15,000 feet. This 
permanent gap of several thousand feet vertical elevation between 
the zone of snow and the zone of forest permits the full extension 
/of many pioneer forest species, Avhich is to say, there is an irregu- 



CLIMATOLOGY OF THE PERUVIAN ANDES 149 

lar development of the cold timber line. It also permits the full 
use of the pasture belt above the timber (Fig. 97), hence perma- 
nent habitations exist but little below the snowline and a group 
of distinctive high-mountain folk enjoys a wide distribution. 
There is a seasonal migration here, but it is not wholesale; there 
are pastures snow-covered in the southern winter, but, instea.d of 
the complete winter burial of the Alpine meadows of our western 
mountains, we have here only a buried upper fringe. All the rest 
of the pasture belt is open for stock the year round. 

This climatic distinction between the lofty grazing lands of the 
tropics and those of the temperate zones is far-reaching. Our 
mountain forests are not utilized from above but from below. 
Furthermore, the chief ways of communication lead around our 
forests, or, if through them, only for the purpose of putting one 
population group in closer touch with another. In the Peruvian 
Andes the largest population groups live above the forest, not be- 
low it or within it. It must be and is exploited from above. 

Hence railways to the eastern valleys of Peru have two chief 
objects, (1) to get the plantation product to the dense populations 
above the forest and (2) to bring timber from the montana to the 
treeless plateau. The mountain prospector is always near a habi- 
tation; the rubber prospector goes down into the forested valleys 
and plains far from habitations. The forest separates the naviga- 
ble streams from the chief towns of the plateau; it does not lead 
down to rich and densely populated valley floors. 

Students in eastern Peru should find it a little difficult to 
understand poetical allusions to silent and lonely highlands in con- 
trast to the busy life of the valleys. To them Shelley's descrip- 
tion of the view from the Euganean Hills of northern Italy, 

" Beneath is spread like a green sea 
The waveless plain of Lombardy, . . . 
Islanded by cities fair," 

might well seem to refer to a world that is upside down. 

There is much variation in the forest types between the moun- 
tains and the plains. At the top of the forest zone the warm 



150 THE ANDES OF SOUTHERN PERU 

sunny slopes have a forest cover; the shady slopes are treeless. 
At the lower edge of the grassland, only the shady slopes are for- 
ested (Fig. 53B). Cacti of arboreal size and form grow on the 
lofty mountains far above the limits of the true forest ; they also 
appear at 3,000 feet in modified form, large, rank, soft-spined, and 
in dense stands on the semi-arid valley floors below the dry timber 
line. Large tracts between 8,000 and 10,000 feet are covered with 
a forest growth distributed by species — ^here a dense stand of one 
type of tree, there another. This is the most accessible part of 
the Peruvian forest and along the larger valleys it is utilized to 
some extent. The number of species is more limited, however, and 
the best timber trees are lower down. Though often referred to 
as jungle, the lowlier growths at the upper edge of the forest zone 
have no resemblance to the true jungle that crowds the lowland 
forest. They are merely an undergrowth, generally open, though 
in some places dense. They are nowhere more dense than many 
examples from New England or the West. 

/ Where deep valleys occur near the border of the mountains 
•^ there is a semi-arid climate below and a wet climate above, with a 
correspondingly greater number of species within short distances 
of each other. This is a far more varied forest than at the upper 
edge of the timber zone or down on the monotonous plains. It 
has a higher intrinsic value than any other. That part of it be- 
tween the Pongo and Yavero (1,200 to 4,000 feet) is very beauti- 
ful, with little undergrowth except a light ground-cover of ferns. 
The trees are from 40 to 100 feet in height with an average 
diameter of about 15 inches. It would yield from 3,000 to 5,000 
board feet per acre exclusive of the palms. There are very few 
vines suspended from the forest crown and the trunks run clear 
from 30 to 60 feet above the ground. Were there plenty of labor 
and a good transportation line, these stands would have high eco- 
nomic value. Among the most noteworthy trees are the soft white 
cedar, strong and light ; the amarillo and the sumbayllo, very dura- 
ble in water; the black nogal, and the black balsam, sti-aight and 
easy to work; the heavy yunquero, which turns pink when dry; 
the chunta or black palm, so hard and straight and easy to split 



f 




Fig. 94. 



I'^Sjf^'w''^ 




Fig. 95. 



Fig. 94 — Cloud belt at 11,000 feet in the Apurimac Canyon near Incahuasl. For a 
regional diagram and a climatic cross-section see Figs. 32 and 33. 

Fig. 95 — The tropical forest near Pabellon on the slopes of the Urubaraba Valley. 
Elevation 3,000 feet (915 m.). 



CLIMATOLOGY OF THE PERUVIAN ANDES 151 

that wooden nails are made from it; and the rarer sandy matico, 
highly prized for dug-out canoes. Also from the chunta palm, hol- 
low except for a few central fibers, easily removed, pipes are made 
to convey Avater. The cocobolo has a rich brown color and a 
glossy surface and is very rare, hence is much sought after for 
use in furniture making. Most of these woods take a brilliant 
polish and exhibit a richness and depth of color and a beauty of 
grain that are rare among our northern woods. 

The plains forest northeast of the mountains is in the zone of 
moderate rainfall where there is one long dry season and one 
long wet season. When it is dry the daytime temperatures rise 
rapidly to such high levels that the relative humidity of the air 
falls below 50 per cent (Fig. 110). The effect on the vegetation is 
so marked that many plants pass into a distinctly wilted condi- 
tion. On clear days the rapid fall in the relative humidity is 
astonishing. By contrast the air on the mountain border heats 
more slowly and has a higher relative humidity, because clouds 
form almost constantly in the ascending air currents and reflect 
and absorb a large part of the heat of the sun's rays. It is strik- 
ing to find large tracts of cane and bamboo on the sand bars and 
on wet shady hillslopes in the slope belt, and to pass out of them 
in going to the plains with which we generally associate a swamp 
vegetation. They exist on the plains, but only in favored, that is 
to say wet, spots. Larger and more typical tracts grow farther 
north where the heavier rains of the Amazon basin fall. 

The floods of the wet tropical season also have a restricting in- 
fluence upon the tropical forest. They deliver such vast quantities 
of water to the low-gradient lowland streams that the plains 
rivers double, even treble, their Avidth and huge pools and even 
temporary lakes form in the shallow depressions back of the 
natural levees. Of trees in the flooded areas there are only those 
few species that can grow standing in water several months each 
year. There are also cane and bamboo, ferns in unlimited num- 
bers, and a dense growth of jungle. These are the haunts of the 
peccary, the red forest deer, and the jungle cat. Except along the 
narrow and tortuous animal trails the country is quite impassa- 



152 THE ANDES OF SOUTHERN PERU 

ble. Thus for the sturdiest and most useful forest growth the 
one-wet-one-dry season zone of the plains has alternately too 
much and too little water. The rubber tree is most tolerant toward 
these conditions. Some of the best stands of rubber trees in Ama- 
zonia are in the southwestern part of the basin of eastern Peru 
and Bolivia, where there is the most typical development of the 
habitat marked by the seasonal alternation of floods and high 
temperatures. 

When tropical agriculture is extended to the plains the long 
dry season will be found greatly to favor it. The southwest- 
ern quadrant of the Amazon basin, above referred to, is the 
best agricultural area within it . The northern limits of the 
tract are only a little beyond the Pongo. Thence northward the 
climate becomes wetter. Indeed the best tracts of all extend from 
Bolivia only a little way into southeastern Peru, and are coinci- 
dent with the patchy grasslands that are there interspersed with 
belts of woodland and forest. Sugar-cane is favored by a climate 
that permits rapid growth with a heavy rainfall and a dry season 
is required for quality and for the harvest. Rice and a multitude 
of vegetable crops are also w-ell suited to this type of climate. 
Even corn can be grown in large quantities. 

At the present time tropical agriculture is almost wholly con- 
fined to the mountain valleys. The reasons are not wholly cli- 
matic, as the above enumeration of the advantages of the plains 
suggests. The consuming centers are on the plateau toward the 
west and limitation to mule pack transport always makes distance 
in a rough country a very serious problem. The valleys combine 
with the advantage of a short haul a climate astonishingly like the 
one just described. In fact it is even more extreme in its seasonal 
contrasts. The explanation is dependent upon precisely the same 
principles we have hitherto employed. The front range of the 
Andes and the course of the Urubamba run parallel for some dis- 
tance. Further, the front range is in many places somewhat 
higher than the mountain spurs and knobs directly behind it. 
Even when these relations are reversed the front range still acts 
as a barrier to the rains for all the deep valleys behind it whose 



CLIMATOLOGY OF THE PERUVL^ ANDES 153 

courses are not directly toward the plains. Tlius, one of the 
largest valleys in Peru, the Urubamba, drops to 3,400 feet at 
Santa Ana and to 2,000 feet at Eosalina, well within the eastern 
scarp of the Andes. The mountains immediately about it are from 
6,000 to 10,000 feet high. The result is a deep semi-arid pocket 
with only a patchy forest (Fig. 54, p. 79).° In places the degree 
of seclusion from the wind is so great that the scrub, cacti, and 
irrigation remind one strongly of the desert on the border 
of an oasis, only here the transition is toward forests instead 
of barren wastes. The dense forest, or montana, grows in the 
zone of clouds and maximum precipitation between 4,000 and 
10,000 feet. At the lower limit it descends a thousand feet 
farther on shady slopes than it does on sunny slopes. The 
continuous forest is so closely restricted to the cloud belt that 
in Fig. 99 the two limits may be seen in one photograph. All 
these sharply defined limits and contrasts are due to the fact 
that the broad valley, discharging through a narrow and remote 
gorge, is really to leeward of all the mountains around it. It 
is like a real desert basin except in a lesser degree of exclusion 
from the rains. If it were narroAV and small the rains formed on 
the surrounding heights would be carried over into it. Eain on 
the hills and sunshine in the valley is actually the day-by-day 
weather of the dry season. In the wet season the sky is overcast, 
the rains are general, though lighter in the valley pocket, and 
plants there have then their season of most rapid growth. The 
dry season brings plants to maturity and is the time of harvest. 
Hence sugar and cacao plantations on a large scale, hence a 
varied life in a restricted area, hence a distinct geographic prov- 
ince unique in South America. 

INTEE-ANDEAN VALLEY CLIMATES 

Not all the deep Andean valleys lie on or near the eastern 
border. Some, like the Apurimac and the Maranon, extend well 

"A dry pocket in the Huallaga basin between 6° and 7° S. is described by Spruce 
(Notes of a Botanist on the Amazon and Andes. 2 vols., London, 1908). Tarapoto at 
an elevation of 1,500 feet above sea level, encircled by hills rising 2,000 to 3,000 feet 
higher, rarely experiences hea^'y rain though rain falls frequently on the hills. 



164 THE ANDES OF SOUTHERN PERU 

into the interior of the Cordillera. Besides these deep remote val- 
leys with their distinct climatic belts are basins, most of them Avith 
outlets to the sea-^broad structural depressions occurring in 
some cases along large and in others along small drainage lines. 
] The Cuzco basin at 11,000 feet and the Abancay basin at 6,000 to 
8,000 feet are typical. Both have abrupt borders, narrow outlets, 
large bordering alluvial fans, and fertile irrigable soil. Their dif- 
ference of elevation occurs at a critical level. Corn will ripen in 
the Cuzco basin, but cane will not. Barley, wheat, and potatoes 
are the staple crops in the one; sugar-cane, alfalfa, and fruit in 
.___the other.j Since both are bordered by high pastures and by min- 
eralized rocks, the deeper Abancay basin is more varied. If it 
were not so difficult to get its products to market by reason of its 
inaccessibility, the Abancay basin would be the more important. 
In both areas there is less rainfall on the basin floor than on the 
surrounding hills and mountains, and irrigation is practised, but 
the deeper drier basin is the more dependent upon it. Many small 
high basins are only within the limits of potato cultivation. They 
also receive proportionately more rain. Hence irrigation is un- 
necessary. According as the various basins take in one or another 
of the different product levels (Fig. 35) their life is meager and 
unimportant or rich and interesting. 

The deep-valley type of climate has the basin factors more 

[strongly developed. Below the Canyon of Choqquequirau, a topo- 

ft graphic feature comparable with the Canyon of Torontoy, the 

I Apurimac descends to 3,000 feet, broadens to several miles, and 

j has large alluvial fans built into it. Its floor is really arid, with 

\ naked gravel and rock, cacti stands, and gnarled shrubs as the 

1 chief elements of the landscape. Moreover the lower part of the 

' valley is the steeper. A former erosion level is indicated in Fig. 

125. When it was in existence the slopes were more moderate than 

rnow and the valley broad and open. Thereupon came uplift and 

the incision of the stream to its present level. As a result, a steep 

canyon was cut in the floor of a mature valley. Hence the slopes 

are in a relation unlike that of most of the slopes in our most 

familiar landscapes. The gentle slopes are above, the steep be- 




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CLIMATOLOGY OF THE PERUVIAN ANDES 155 

low. The break between the two, a topographic unconformity, 
may be distinctly traced. 

Combined with these topographic features are certain climatic 
features of equal precision. Between 7,000 and 13,000 feet is a 
zone of clouds oftentimes marked out as distinctly as the belt of 
fog on the Peruvian coast.^ Earely does it extend across the val- 
ley. Generally it hangs as a white belt on the opposite walls. 
When the up-valley winds of day begin to blow it drifts up-valley, 
oftentimes to be dissolved as it strikes the warmer slopes of the 
upper valley, just as its settling under surface is constantly being 
dissolved in the warm dry air of the valley floor. Where the pre- 
cipitation is heaviest there is a belt of woodland — dark, twisted 
trees, moss-draped, wet — a Druid forest. Below and above the 
woodland are grassy slopes. At Incahuasi a spur runs out and 
down until at last it terminates between two deep canyons. No 
ordinary wells could be successful. The ground water must be 
a thousand feet down, so a canal, a tiny thing only a few inches 
wide and deep, has been cut away up to a woodland stream. 
Thence the water is carried down by a contour-like course out of 
the woodland into the pasture, and so down to the narrow part of 
the spur where there is pasture but no springs or streams. 

Corn fields surround the few scattered habitations that have 
been built just above the bre"''' or shoulder on the valley wall 
where the woodland terminates, and there are fine grazing lands. 
The trails follow the upper slopes whose gentler contours permit 
a certain liberty of movement. Then the way plunges downward 
over a staircase trail, over steep boulder-strewn slopes to the arid 
floor of a tributary where nature has built a graded route. And 
so to the still more arid floor of the main valley, where the ample 
and moderate slopes of the alluvial fans with their mountain 
streams permit plantation agriculture again to come in. 

To these three climates, the western border type, the eastern 

• Speaking of C6mas situated at the headwaters of a source of the Perene amidst 
a multitude of quebradas Kaimondi (op. cit., p. 109) says it "might properly be called 
the town of the clouds, for there is not a day during the year, at any rate towards 
the evening, when the town is not enveloped in a mist sufficient to hide everything 
from view." 



156 THE ANDES OF SOUTHERN PERU 

border type, and tlie inter-Andean type, we have given chief at- 
tention because they have the most important human relations. 
The statistical records of the expedition as sho^\^l in the curves 
and the discussion that accompanies them give attention to those 
climatic features that are of theoretical rather than practical inter- 
est, and are largely concerned with the conventional expression 
of the facts of weather and climate. They are therefore com- 
bined in the following chapter Avliich is devoted chiefly to a tech- 
nical discussion of the meteorology as distinguished from the 
climatology of the Peruvian Andes. 



CHAPTER X 
METEOROLOGICAL RECORDS FROM THE PERUVIAN ANDES 

Intkoduction 

The data in this chapter, on the weather and climate of the 
Peruvian Andes, were gathered under the usual difficulties that ac- 
company the collection of records at camps scarcely ever pitched 
at the same elevation or with the same exposure two days in suc- 
cession. Some of them, and I may add, the best, were contributed 
by volunteer observers at fixed stations. The observations are 
not confined to the field of the Yale Peruvian Expedition of 
1911, but include also observations from Professor Hiram Bing- 
ham's Expeditions of 1912 and 1914-15, together with data from 
the Yale South American Expedition of 1907. In addition I 
have used observations supplied by the Morococha Mining Com- 
pany through J. P. Little. Some hitherto unpublished observa- 
tions from Cochabamba, Bolivia, gathered by Herr Kriiger at con- 
siderable expense of money for instruments and of time from a 
large business, are also included, and he deserves the more credit 
for his generous gift of these data since they Avere collected for 
scientific purposes only and not in connection with enterprises in 
which they might be of pecuniary value. My only excuse to Herr 
Kriiger for this long delay in publication (they were put into my 
hands in 1907) is that I have wanted to publish his data in a digni- 
fied form and also to use them for comparison with the data of 
other climatic provinces. 

A further word to the reader seems necessary before he ex- 
amines the following curves and tables. It would be somewhat 
audacious to assume that these short-term records have far-reach- 
ing importance. Much of their value lies in their organization 
with respect to the data already published on the climate of Peru. 
But since this would require a delay of several years in their pub- 
lication it seems better to present them now in their simplest 
form. After all, the professional climatologist, to Avhom they are 

157 



158 



THE ANDES OF SOUTHERN PERU 



chiefly of interest, scarcely needs to have such organization sup- 
plied to him. Then, too, we hope that there Avill become available 
in the next ten or fifteen years a vastly larger body of climato- 
logical facts from this region. When these have been collected 
we may look forward to a volume or a series of volumes on the 
"Climate of Peru," with full statistical tables and a complete dis- 
cussion of them. That would seem to be the best time for the re- 
production of the detailed statistics now on hand. It is only nec- 
essary that there shall be sufficient analysis of the data from time 
to time to give a general idea of their character and to indicate 
in what way the scope of the observations might profitably be ex- 
tended. I have, therefore, taken from the available facts only 
such as seem to me of the most importance because of their un- 
usual character or their special relations to the boundaries of 
plant provinces or of the so-called "natural regions" of 
geography. 

Machu Picchu ^ 
The following observations are of special interest in that they 
illustrate the weather during the southern Avinter and spring at 
the famous ruins of Machu Picchu in the Canyon of Torontoy. 
The elevation is 8,500 feet. The period they cover is too short to 
give more than a hint of the climate or of the weather for the 
year. It extends from August 20, 1912, to November 6, 1912 (79 
days). 

ANALYTICAL TABLE OF WIND DIRECTIONS, MACHU PICCHU, 1912 





Number of ObBervations 


Direction of wind 


Aug. 20 — Sept. 30 
7a. m. 1 p. m. 7p. m. 


Oct. 1 — Nov. 6 
7 a. m. 1 p. m. 7 )>. m. 


N 


5 2 5 
9 10 14 

— 1 2 

— — 1 

— — 1 
4 2 1 

6 3 3 
8 7 6 


o 


N. W 


4 6 11 

2 2 4 


w 


s. w 


116 


s 


S. E 


— — 3 

12 4 4 

4 13 

5 3 3 


E 


N. E 


CALM 







'Observer: E. C. Erdis of the 1912 and 1914-15 Expeditions. 



METEOROLOGICAL RECORDS 



159 



Direction of wind 



Percentages of Total Observations ^ 



Aug. 20 


_ 


Sept. 30 


Oct.l 


_ 


Nov. 6 


7 a. m. 


1 p. m. 


7 p. m. 


7 a. m. 


1 p. m. 


7 p. m. 


15.6 


8.0 


14.2 


6.7 






28.1 


40.0 


40.0 


13.3 


35.3 


30.7 




4.0 


5.7 


6.7 


11.8 


11.1 






2.8 


3.3 


5.9 


16.7 






2.8 






5.5 


12.5 


8.0 


2.8 






8.3 


18.8 


12.0 


8.6 


40.0 


23.5 


11.1 


25.0 


28.0 


17.1 


13.3 


5.9 


8.3 






5.7 


16.7 


17.6 


8.3 



N 

N. W. 
W. ... 

s. w. , 

s 

S. E. . 
E 

N. E. . 
CALM 



The Mgli percentage of northwest winds during afternoon 
hours is due to the up-valley movement of the air common to almost 
all mountain borders. The air over a mountain slope is heated 
more than the free air at the same elevation over the plains (or 

N , N „ N 



7 a.m. 




1 p.m. 





Fig. 100 — Wind roses for Machu Piccliu, August 20 to November 6, 1912. 

lower valley) ; hence a barometric gradient towards the mountain 
becomes established. At Machu Picchu the Canyon of Torontoy 
trends northwest, making there a sharp turn from an equally 
sharp northeast bend directly upstream. The easterly components 
are unrelated to the topography. They represent the trades. If 
a wind rose were made for still earlier morning hours these winds 
would be more faithfully represented. That an easterly and 
northeasterly rather than a southeasterly direction should be as- 
sumed by the trades is not difficult to believe when we consider 
the trend of the Cordillera — southeast to northwest. The observa- 



' Percentages given because the number of observations varies. 



160 



THE ANDES OF SOUTHERN PERU 



tions from here down to the plains all show that there is a distinct 
change in wind direction in sympathy with the larger features of 
the topography, especially the deep valleys and canyons, the trades 



coming in from the northeast. 



CLOUDINESS 

It will be seen that the sky was overcast or a fog lay in the 
valley 53 per cent of the time at early morning hours. Even at 
noon the sky was at no time clear, and it was more than 50 per 
cent clear only 18 per cent of the time. Yet this is the so-called 
"dry" season of the valleys of the eastern Andes. The rainfall 
record is in close sympathy. In the 79 days' observations rain is 
recorded on 50 days Avith a greater proportion from mid-Septem- 
ber to the end of the period (November 6), a distinct transition 
toward the wet period that extends from December to May. The 
approximate distribution of the rains by hours of observation 
(7 A. M., 1 p. M., 7 p. M.) was in the ratio 4:3:6. Also the greatest 
number of heavy showers as well as the greatest number of 
showers took place in the evening. The rainfall was apparently 
unrelated to wind direction in the immediate locality, though un- 
doubtedly associated with the regional movement of the moist 
plains air toward the mountains. All these facts regarding 
clouds and rain plainly show the location of the place in the belt 
of maximum precipitation. There is, therefore, a heavy cover of 
vegetation. While the situation is admirable for defence, the 
murky skies and frequent fogs somewhat offset its topographic 
surroundings as a lookout. 

ANALYTICAL TABLE OF THE STATE OF THE SKY, MACHU PICCHXJ 1912 



Foggy 

Overcast 

50-100% cloudy 
0-50% cloudy . 
Clear 



Morninfj 



Ang. 
Sept. 

3.0 
12.0 
4.0 
6.0 
3.0 



Oct.- 
Nov. 

14.0 
3.0 

10.0 
4.0 
1.0 



Total 



Days 

17.0 
15.0 
14.0 
10.0 
4.0 



28.4 
25.0 
23.3 
16.7 
6.6 



Noon 



Aug.- 
Sept. 

1.0 
6.0 
9.0 

5.0 
0.0 



Oct.. 
Nov. 



8.0 
7.0 
2.0 
0.0 



Total 



Days 

1.0 

14.0 

16.0 

7.0 

0.0 



2.6 
36.S 
42.2 
18.4 

0.0 



Evening 



Ang.- 
Sept. 

1.0 

13.0 

8.0 

9.0 

3.0 



Oct.. 
Nov. 

2.0 

11.0 

15.0 

4.0 

3.0 



Toial 



Days 
3.0 

24.0 

23.0 

13.0 

6.0 



4.3 
34.8 
33.3 
18.8 

8.8 



METEOROLOGICAL RECORDS 



161 



Santa Lucia ^ ^_^ 

Santa Lucia is a mining center in the province of Puno (16° 
S.), at the head of a valley here running northeast towards Lake 
Titicaca. Its elevation, 15,500 feet above sea level, confers on it 
unusual interest as a meteorological station. A thermograph has 
been installed which enables a closer study of the temperature to be 
made than in the case of the other stations. It is unfortunate, how- 
ever, that the observations upon clouds, wind directions, etc., should 
not have been taken at regular hours. The time ranges from 8.30 
to 11.30 for morning hours and from 2.30 to 5.30 for afternoon. 
The observations cover portions of the years 1913 and 1914. 



■ TEMPEEATUEE 

Perhaps the most striking features of the weather of Santa 
Lucia are the highly regular changes of temperature from night 
to day or the uniformly great diurnal range and the small dif- 
ferences of temperature from day to day or the low diurnal 
variability. For the whole period of nearly a year the diurnal 
variability never esceeds 9.5° F. (5.3° C.) and for days at a time 
it does not exceed 2-3° F. (1.1°-1.7° C). The most frequent varia- 
tion, occurring on 71 per cent of the total number of days, is from 
0-3° F., and the mean for the year gives the low variability of 
1.9° F. (1.06° C). These facts, illustrative of a type of weather 
comparable in uniformity with low stations on the Ajnazon plains, 
are shown in the table following as well as in the accompanying 
curves. 

FREQUENCY OF THE DIURNAL VARIABILITY, SANTA LUCIA, 1913-14 



Degrees F. 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


March 


Total No. 
of days 








2 


6 


3 


4 


6 


2 





1 





2 


26 


0-1 


2 


7 


7 


5 


6 


4 


8 


12 


14 


9 


5 


79 


1-2 


11 


5 


7 


11 


7 


8 


5 


5 


4 


9 


13 


85 


2-3 


2 


8 


8 


9 


3 


7 


7 


5 


5 


4 


G 


64 


3-4 


4 


4 


2 


1 


4 


1 


3 


6 


2 


4 


2 


33 


4-5 


1 


3 


1 


— 


2 


1 


3 


— 


2 


1 


1 


15 


Over 5 


— 


1 


— 


2 


4 


4 


2 


2 


3 


1 


— 


19 


Days pel 


20 


30 


31 


31 


30 


31 


30 


30 


31 


28 


29 


321 


month 



























^ Observer : Senor Valdivia. For location of Santa Lucia see Fie. 



162 THE ANDES OF SOUTHERN PERU 

If we take the means of the diurnal variations by months we 
have a still more striking curve showing how little change there 
is between successive days. June and December are mai'ked by 
humps in the curve. They are the months of extreme weather 
when for several weeks the temperatures drop to their lowest or 
climb to their highest levels. Moreover, there is at these lofty 
stations no pronounced lag of the maximum and minimum tem- 
peratures for the year behind the times of greatest and least heat- 
ing such as we have at lower levels in the temperate zone. Thus 
we have the highest temperature for the year on December 2, 
70.4° F. (21.3° C), the lowest on June 3, 0.2° F. (—17.7° C). The 
daily maxima and minima have the same characteristic. Radiation 
is active in the thin air of high stations and there is a very 
direct relation between the times of greatest heat received and 
greatest heat contained. The process is seen at its best immedi- 
ately after the sun is obscured by clouds. In five minutes I have 
obsei-ved the temperature drop 20° F. (11.1° C.) at 16,000 feet 
(4,877 m.) ; and a drop of 10° F. (5.6° C.) is common anywhere 
above 14,000 feet (4,267 m.). In the curves of daily maximum and 
minimum temperatures we have clearly brought out the uniform- 
ity with which the maxima of high-level stations rise to a mean 
level during the winter months (May- August). Only at long in- 
tervals is there a short series of cloudy days when the maximum 
is 10°-12° F. (5.6°-6.7° C.) below the normal and the minimum 
stands at abnormally high levels. Since clouds form at night 
in quite variable amounts — in contrast to the nearly cloud- 
less days — there is a far greater variability among the minimum 
temperatures. Indeed the variability of the winter minima 
is greater than that of the summer minima, for at the latter 
season the nightly cloud cover imposes much more stable atmos- 
pheric temperatures. The summer maxima have a greater 
degree of variability. Several clear days in succession allow 
the temperature to rise from 5°-10° F. (2.8°-5.6° C.) above 
the winter maxima. But such extremes are rather strictly 
confined to the height of the summer season — December and 
January. For the rest of the summer the maxima rise only 



TALI 



No 



Re( 



t7tv?'= 



V^ 



, SAN' 



\^'- ' 



r-^-\y\ 



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[o RecCT 



MARCH 



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m 



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40' 



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10 



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—IS?- 











MARCH 










APRIL 






60° 
50° 
40° 
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20 






















































































































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iO 



RATURE, SANTA LTTCTA, 1913-'14 
0. 



i, 1913 



(jent 

100 

Morning 

nr- 90 
Afte rnoon 

SO 




FIG. 101 A - DIURT^AL TEMPERATURE, SANTA LUCIA 1913 -'14 




0. 


p. 

















































FIG 


. 101 c - 

1 


DIURNAL RANGE OF TEMPERATURE, SANTA LUCIA, 1913-14 

1 i InPTi 1 i n 1 iMnvl 1 1 r-| i TnSrn 




















































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FIG 


101 E 


DIURNAL VARIABILITY OF TEMPERATURE 


, SANTA LUCIA, 1913-'14 










































K 






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FIG. 101 B - MEAN MONTHLY TEMPERATURE, SANTA LUCIA, 1913-'14 

K\ 

60- 



UAV 


TUNl'Jl'LV 


AUOjSEPI 


OCT. 


NOV. 


DEC. 


.TAN. 


FEB. 


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FIG. 101 D -TMONTHLY MEANS OF DIURNAL EAKGB OF TEMPERATURE, SANTA LUCIA, 1913-'14 



Kc 


MAyliL'N4JLiL\lAllG 


SEP1 


OCT. 


NOV. 


DEO. 


JAN. 


FEB. 


MAIt 


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16" 



FIG. 101 F- RELATIVE HUMIDITY, SANTA LUCIA, 1913-'14 



METEOROLOGICAL RECORDS 163 

a few degrees above those of the winter. This feature of the 
climate combines with a December maximum of rainfall to limit 
the period of most rapid plant growth to two months. Bar- 
ley sown in late November could scarcely mature by the end of 
January, even if growing on the Argentine plains and much less 
at an elevation which carries the night temperatures below freez- 
ing at least once a week and where the mean temperature hovers 
about 47° F. (8.3° C). The proper conditions for barley growing 
are not encountered above 13,000 to 13,500 feet and the farmer 
cannot be certain that it will ripen above 12,500 feet in the lati- 
tude of Santa Lucia. 

The curve of mean monthly temperatures expresses a fact of 
great importance in the plant growth at high situations in the 
Andes — the sharp break between the winter and summer seasons. 
There are no real spring and autumn seasons. This is especially 
well shown in the curve for non-periodic mean monthly range of 
temperature for the month of October. During the half of the 
year that the sun is in the southern hemisphere the sun's noon- 
day rays strike Santa Lucia at an angle that varies between 0° and 
16° from the vertical. The days and nights are of almost equal 
length and though there is rapid radiation at night there is also 
rapid insolation by day. When the sun is in the northern hemi- 
sphere the days are shortened from one to two hours and the angle 
of insolation decreased, whence the total amount of heat received 
is so diminished that the mean monthly temperature lies only a 
little above freezing point. In winter the quiet pools beside the 
springs freeze over long before dark as the hill shadows grow 
down into the high-level valleys, and by morning ice also covers 
the brooks and marshes. Yet the sun and wind-cured ichu grass 
lives here, pale green in summer, straw-yellow in winter. The 
tola bush also grows rather abundantly. But we are almost 
at the upper limit of the finer grasses and a few hundred feet 
higher carries one into the realm of the snowline vegetation, 
mosses and lichens and a few sturdy flowering plants. 

For convenience in future comparative studies the absolute 
extremes are arranged in the following table: 



164 THE ANDES OF SOUTHERN PERU 

ABSOLUTE MONTHLY EXTREMES, SANTA LUCIA, 1913-14 



t/ 



Date 


Ili^hcet 


Lowuft 


Dalo 


May* (12) 


62° F. 


9°F. 


May (25, 26) 


June (4 days) 


60° F. 


0.2° F. 


June (3) 


July (4 days, 31) 


60° F. 


5° F. 


July (S) 


Aug. (8, 26) 


62° F. 


4°F. 


Aug. (4, 5) 


Sept. (several days) 


62° F. 


7°F. 


Sept. (4 days) 


Oct. (24) 


63° F. 


10° F. 


Oct. (12, 13) 


Nov. (11) ° 


63° F. 


24.0° F. 


Nov. (29) 


Dee. (2) 


70.4° F. 


22.2° F. 


Dec. (14) 


Jan. (19) 


69.5° F. 


26.5° F. 


Jan. (3, 15) 


Feb. (16,1S) 


63.2° F. 


30.5° F. 


Feb. (23) 


March (S) 


68.4° F. 


2.S.5° F. 


]\[arcli (6) 



EAINEALL 

The rainfall record for Santa Lucia is for the year beginning 
November, 1913. For this period the precipitation amounts to 
24.9 inches of which over 85 per cent fell in the rainy season from 
November to March. Most of the rain fell during the violent after- 
noon tempests that characterize the summer of these high alti- 
tudes. 

The rainfall of Santa Lucia for this first year of record ap- 
proximates closely to the yearly mean of 23.8 inches for the sta- 
tion of Caylloma in the adjacent province of that name. Caylloma 
is the center of a mining district essentially similar to Santa 
Luoia though the elevation of its meteorological station, 14,196 
feet (4,330 m.), is lower. It is one of the few Peruvian stations 
for which a comparatively long series of records is available. The 
Boletin de la Sociedad Geogrdfica de Lima ° contains a resume of 
rainfall and temperature for seven years, 1896-7 to 1902-3. Later 
data may be found in subsequent volumes of the same publication 
but they have not been summarized or in any way prepared for 
analysis and they contain several tj^ographical errors. A graphic 
representation of the monthly rainfall for the earlier period is 
here reproduced from the Boletin de minas del Peru.'' The 

' Observations began on May 12. 

° For the first half of the month only; no record for the second half. 
° Boletin de la Sociedad Geogrfifica de Lima, Vol. 13, pp. 47.3-480, Lim.i, 1903. 
' Boletin del Cuerpo de Ingenieros de Minas del Perrt, No. 34, Lima, 1905, also 
reproduced in No. 45, 1906. 



METEOROLOGICAL RECORDS 



165 



IN. 



10- 



--300 



--250 



MM. IN. 
12 



-200 



■150 ^ 



100 4- 



= -60 



--200 



11 



i_H Q_ 



MM. 
-300 



-250 



-150 



-100 



N. D. J. E. M. A. M. J. J. A. S. O. 
Fig. 102. 



J. p. M. A. M. J. J. A. S. O. N. D. 
Fig. 103A. 



IN. 



30- 



20- 



10- 



CAYLLOMA 



SANTA 
LUCIA 



MM. 



-1000 



«00 



-600 



= -400 



-200 



t- CO CD O 

to t- OO 2 



u3 to t— 00 a> o 



s a 






■a 



s 



Fig. 103B. 

Fig. 102 — Monthly rainfall of Santa Lucia for the year November, 1913, 
to October, 1914. No rain fell in July and August. 

FiQ. 103A — Maximum, mean and minimum monthly rainfall of Caylloma 
for the period 1896-7 to 1902-3. July was absolutely rainless. Caylloma is 
situated immediately east of the crest of the Maritime Cordillera in a position 
similar to that of Santa Lucia (see Fig. 66). 

Fie. 103B — Annual rainfall of Caylloma for the periods 1896-7 to 1902-3; 

1903-4 to 1910-11 and for 1915-6 (incomplete: May and June, months of low 

rainfall, are missing). Means for the respective seven and eight year periods are 

shovm and the rainfall of Santa Lucia for the single observation year is inserted 

for comparison. 



166 



THE ANDES OF SOUTHERN PERU 



amount of precipitation fluctuates considerably from year to year. 
For the earlier period, with a mean of 23.8 inches the minimum 
(1896-7) was 8 inches and the maximum (1898-9) 36 inches. For 
the later period, 1903-4 to 1910-11, with a mean of 29.5 inches the 
minimum (1904-5) was 17.5 inches and the maximum (1906-7) was 
43 inches. 



RAINFALL, SANTA LUCLA., NOV. 1913 TO OCT. 1914 





No of 
flue daya 


No. of 
rainy days 


Mm. for 
single tiny 


Total riiinfnll 
in inclicB 


November 


9 

16 
17 

9 
11 
17 

8 

27 
31 
31 
23 
21 


21 

15 

14 

17 

20 

13 

23 

3 





7 

10 


1.150 
.700 
.CIO 
.910 
1.102 
0.31 
0.35 
0.05 
0.00 
0.00 
0.05 
0.14 


4.2G4 " 


December 


0.439 


January 


3.313 




2.975 


March 


4.3S1 


April 


0.92 


May 


1.03 




0.07 


July 


0.00 


August 


0.00 


September 


0.35 


October 


0.56 






Total 








24.902 



WIND 

An analysis of the wind at Santa Lucia shoAvs an excess of 
north and south winds over those of all other directions. The 
wind-rose for the entire period of observation (Fig. 104) clearly 
expresses this fact. When this element is removed we observe a 
strongly seasonal distribution of the wind. The winter is the time 
of north and south winds. In summer the winds are chiefly from 
the northeast or the southwest. Among single months, August 
and February show this fact clearly as well as the less decisive 
character of the summer (February) wind. 

The mean -wind velocity for the month of February was 540 
meters per minute for the morning and 470 meters per minute for 
the afternoon. The higher morning rate, an unusual feature of 

' The record is copied literally without regard to the absurdity of the second 
and third decimal places. 



METEOROLOGICAL RECORDS 



167 



JUN£, 1913 




OCT. 



FEB. 




Fig. 104 — Monthly wind roses for Santa Lucia, June, 1913, to July, 1914, and 
composite rose for the whole period of observation. 



168 



THE ANDES OF SOUTHERN PERU 



the weather of high stations, or indeed of wind-phenomena in gen- 
eral, is due, however, to exceptional changes in wind strength on 
two days of the month, the 16th and 25th, when the velocity de- 
creased from a little less than a thousand meters per minute in 
the morning to 4 and 152 meters respectively in the afternoon. 
More typical is the March record for 1914 at Santa Lucia, when 
the wind was always stronger in the afternoon than in the morn- 
ing, their ratios being 550 to 510. 



CLOUD 

The greater strength of the afternoon wind would lead us to 
suppose that the cloudiness, which in the trade-wind belt, is to so 
great an extent dependent on the Avind, is greatest in the after- 
noon. The diagrams bring out this fact. Earely is the sky quite 
clear after the noon hour. Still more striking is the contrast be- 
tween the morning and afternoon if Ave combine the tAvo densest 
shadings of the figures. Light, high-lying cirrus clouds are most 
characteristic of early morning hours. They produce some very 
striking sky effects just before sunrise as they catch the sun's rays 
aloft. An hour or tAvo after sunrise they disappear and small 
cumulus clouds begin to form. These groAv rapidly as the Avinds 
begin and by afternoon become bulky and numerous. In the wet 
season they groAv into the nimbus and stratus types that precede 
a sudden downpour of water or a furious hailstorm. This is best 
seen from the base of a mountain range looking towards the crest, 
Avhere the cloud- and rain-making processes of this tj'pe are most 
active. 

CLOUD ANALYSIS, SANTA LUCIA 



Type of cloud 



Nov. 
Ji. m. p. 



Cirrus 

Cirro-stratus . 
Cirro-cumulus . 

Cumulus 

Strato-cumulus 

Stratus 

Nimbus 

Clear 



Dec. 
a. m. p. 



15 

7 
4 
3 



11 
7 

10 
1 



Jan. 
a. m. p. 



3 
10 

7 



5 

9 

14 



Feb. 
in. p. : 



March 
a. m, p. n 



6 

15 
2 



8 

13 

3 

1 



17 10 

5 13 

— 3 

1 2 



Total 
a. m. p. m. 

41 12 



37 

37 

14 

9 



38 
46 
36 

4 



METEOROLOGICAL RECORDS 



169 



■UNUSUAL WEATHEE PHENOMENA, SANTA LUCIA, 1913-14 

The following abstracts are selected because they give some 
important features of the weather not included in the preceding 
tables and graphs. Of special interest are the strong contrasts 




May 




1 Clear 



B§i^ (^2.5 



Scale of Cloudiness 
2.5-7.5 



7.5-10 



Completely 
Overcast 



Fig. 105 — Monthly cloudiness of Santa Lucia from January to July, 1914. Mean 
cloudiness for the whole period is also shown. 

between the comparatively high temperatures of midday and the 
sudden "tempests " accompanied by rain or hail that follow the 
strong convectional movements dependent upon rapid and unequal 
heating. The furious winds drive the particles of hail like shot. 
It is sometimes impossible to face them and the pack train must 



170 THE ANDES OF SOUTHERN PERU 

be halted until the storm has passed. Frequently they leave the 
ground white with hailstones. We encountered one after another 
of these "tempestades" on the divide between Lambrama and 
Antabamba in 1911. They are among the most impetuous little 
storms I have ever experienced. The longest of them raged on 
the divide from two-o'clock until dark, though in the valleys the 
sun Avas shining. Fortunately, in this latitude they do not turn 
into heavy snowstorms as in the Cordillera of northwestern 
Argentina, where the passes are now and then blocked for weeks at 
a time and loss of human life is no infrequent occurrence." They 
do, however, drive the shepherds down from the highest slopes to 
the mid-valley pastures and make travel uncomfortable if not 
unsafe. 

ABSTRACT FROM DAILY WEATHER OBSERVATIONS, SANTA LUCIA, 1913-14 

NOVEMBER 

" Tempest " recorded 11 times, distant thunder and lightning 9 times. 
Unusual weather records: " clear sky, scorching sun, good weather" (Nov. 29) ; 
"morning sky without a single cloud, weather agreeable" (Nov. 30). 

DECEMBER 

Clear morning sky 6 times. Starry night or part of night 7 times. 

Beginning of rain and strong wind frequently observed at 5-6 p. M. 

" Tempest " mentioned 19 times — 5 times at midnight, 8 times at 5-6 p. m. 

JANUARY 

Clear morning sky 5 times. Starry night 3 times. 

Rain, actual or threatening, characteristic of afternoons. 

" Tempest," generally about 5-6 p. m., 7 times. 

Sun described 4 times as scorching and, when without wind, heat as stifling. 

Weather once " agreeable." 

FEBRUARY 

Constant cloud changes, frequent afternoon or evening rains. 
" Tempest," generally 4 p. m. and latei-, 16 times. 

° In the Eastern Cordillera, however, snowstorms may be more serious. Prior to 
the construction of the Urubamba Valley Road by the Peruvian government the three 
main routes to the Santa Ana portion of the valley proceeded via the passes of Salcantay, 
Panticalla, and Yanahuara respectively. Frequently all are completely snow-blocked 
and fatalities are by no means unknown. In 1864 for instance nine persons succumbed 
on the Yanahuara pass (Raimondi, op. cit., p. 109). 



METEOROLOGICAL RECORDS 171 

MARCH 

Twice clear morning skies, once starry night. 
Scorching sun and stifling heat on one occasion. 

" Tempest," generally in late afternoon and accompanied by hail, 19 times. 
Observed 3 or 4 times a strong " land breeze" (terral) of short duration (15-20 
min s.) and at midnight. 

MOEOCOCHA ' — I 

Morococha, in the Department of Ancaclis, Peru, lies in 76° 11' 
west longitude and 11° 45' south latitude and immediately east of 
the crest line of the Maritime Cordillera. It is 14,300 feet above 
sea level, and is surrounded by mountains that extend from 1,000 
to 3,000 feet higher. The weather records are of special interest 
in comparison with those of Santa Lucia. Topographically the 
situations of the two stations are closely similar hence we may 
look for climatic differences dependent on the latitudinal differ- 
ence. This is shown in the heavier rainfall of Morococha, 4° 
nearer the equatorial climatic zone. (For location see Fig. 66.) 

The meteorological data for 1908-09 were obtained from rec- 
ords kept by the Morococha Mining Company for use in a pro- 
jected hydro-electric installation. Other data covering the years 
1906-11 have appeared in the bulletins of the Sociedad Geogrd- 
fica de Lima. These are not complete but they have supplied rain- 
fall data for the years 1910-11 ; " those for 1906 and 1907 have 
been obtained from the Boletin de Minas.^^ 

Tempeeatube 
The most striking facts expressed by the various temperature 
curves are the shortness of the true winter season — its restriction 
to June and July — and its abrupt beginning and endTj^ This is well 
known to anyone who has lived from April to October or Novem- 
ber at high elevations in the Central Andes. Winter comes on 
suddenly and with surprising regularity from year to year dur- 
ing the last few days of May and early June. In the last week of 
July or the first^week of August the temperatures make an equally 
sudden rise. > During 1908 and 1909 the mean temperature reached 
the freezing point but once each year — July 24 and July 12 re- 

•"Boletrn de la Sociedad Geografica de Lima, Vol. 27, 1911; Vol. 28, 1912. 
'' Boletin del Cuerpo de Ingenieros de Minas del Perfl, No. 65, 1908. 



172 THE ANDES OF SOUTHERN PERU 

spectively. The absolute miiLimum for the two years was - 22° C. 
July of 1908 and June of 1909 are also the months of smallest 
diurnal variability, showing that the winter temperatures are 
maintained with great regularity. Like all tropical high-level sta- 
tions, Morococha exhibits winter maxima that are very high as 
compared with the winter maxima of the temperate zone. In both 
June and July of 1908 and 1909 the maximum was maintained for 
about a week above 55° F. (12.8° C), and in 1909 above 60° F. 
(15.6° C), the mean maximum for the year being only 4.7° F. 
higher. For equal periods, however, the maxima fell to levels 
about 10° F. below those for the period from December to 
May, 1908. 

It is noteworthy that the lowest maximum for 1909 was in 
October, 44° F. (6.7° C.) ; and that other low maxima but little 
above those of June and July occur in almost all the other months 
of the year. While 1909 was in this respect an exceptional year, 
it nevertheless illustrates a fact that may occur in any month of 
any year. Its occurrence is generally associated with cloudiness. 
One of the best examples of this is found in the January maximum 
curve for 1909, where in a few days the maxima fell 12° F. Cloud 
records are absent, hence a direct comparison cannot be made, but 
a comparison of the maximum temperature curve with the graphic 
representation of mean monthly rainfall, will emphasize this rela- 
tion of temperature and cloudiness. February was the wettest 
month of both 1908 and 1909. In sympathy with this is the large 
and sharp drop from the January level of the maxima — the highest 
for the year — to the February level. The mean temperatures are 
affected to a less degree because the cloudiness retards night radia- 
tion of heat, thus elevating the maxima. Thus in 1908 the lowest 
minimum for both January and February was 28.4° F. ( — 2° C). 
For 1909 the minima for January and February were 27.5° F. 
(—2.5° C.) and 29.3° F. (—1.5° C.) respectively. 

The extent to which high minima may hold up the mean tem- 
perature is shown by the fact that the mean monthly tempera- 
ture for January, 1908, Avas lower than for February. Single 
instances illustrate this relation equally well. For example, on 



COCH 
































F 


n 


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F. G 




lANGE OF TEMPERATURE, MOROCOCHA 




P. Ol 



-15 
.10° 



FIG. 106 A - DIURNAL TEMPERATURE, MOROCOCHA, 1908 




?F& 



P 



'.7~K 



^CZ 



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m±:i 



^ 



hi 



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so 



0, 


F 
























































FIG. 105 B 


- DIURNAL TEMPERATURE, MOROCOCHA, 1909 


























































Of~ 


^^ 


/ 








— 




t'l 


JB. 




— 


/I 








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FIG. 


106 D- 


DIURNAL 


RA 


NG 


SOI 


'TI 


:mp 


ERj 


^TU 


RE 


MOROCOCHA 


, 1908 


















» 


































T 


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J,AN. 








I 




FEB. 










MA 


kCH 










APRIL 1 








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DEC. 




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C. E 



FIG. 106 E - DIURNAL RANGE OF TEMPERATURE, MOROCOCHA, 1909 



JTJNE 



^ct: 



jAnT 



^W 



JULY 



AUG 



^ 



£5' 



DUJRKIAL RANGE 



(NO ^(-PERIODIC 



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C.E 



FIG. 106 G - DIURNAL VARIABILITY OP TEMPERATURE, MOROCOCHA, 1908 




FIG. 106 C - MEAN MONTHLY TEMPERATURE, MOROCOCHA 
















FIG. 


106 F - 


MONTHLY MEANS OF DIURNAL RANGE OF TEMPERATURE, MOROCOCHA 












F. 


o. 


F. 


J. 


K 


BI. 


A. 


M. 


J. 1 J. 


A. 


S. 


0. 


N. 


D. 


J. 


f. 


M. 


A. 


M. 


J. 


J. 


A. 


S. 


0. A'. 


U. 


.). 










■ 


J= 


=L 


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u. 






50° 


la- 
in" 


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2CP 








=-= 


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■Re'an, 

19l)8L]90f 











s 


40° 



METEOROLOGICAL RECORDS 



173 



March 5th, 1908, there occurred the heaviest rainfall of that year. 
The maximum and minimum curves almost touch. The middle of 
April and late September, 1909, are other illustrations. The rela- 
tionship is so striking that I have put the two curves side by side 
and have had them drawn to the same scale. 

FREQUENCY OF THE DIUKNAL VAEIABILITY, MOROCOCHA, 1908 AND 1909 

1908 



Degrees P. 


J. 


F. 


M. 


A. 


M. 


J. 


J. 


A. 


s. 


0. 


N. 


D. 


Total No. 
of days 








3 


2 


3 








2 


1 


3 


1 


1 


3 


19 


0-1 


6 


5 


6 


10 


9 


10 


13 


10 


8 


6 


6 


5 


94 


1-2 


4 


1 


3 


7 


5 


3 


7 


7 


8 


6 


6 


4 


61 


2-3 


6 


1 


3 


4 


9 


2 


2 


4 


4 


7 


7 


4 


53 


3-4 


5 


3 


2 


3 


3 


4 


2 


9 


4 


5 


3 


5 


48 


4-5 


2 


3 


1 


1 


2 


5 


5 


— 


1 


1 


6 


3 


30 


Over 5 


3 


4 


3 


2 


3 


6 


— 


— 


2 


5 


1 


5 


34 


Days per 


26 


20 


20 


30 


31 


30 


31 


31 


30 


31 


30 


29 


339 


month 





























19(19 



Degrees F. 


J. 


F. 


M. 


A. 


M. 


J. 


J. 


A. 


s. 


0. 


N. 


D. 


Tolnl 
No. of 
days 


Mean 

for 1908 

-1909 





6 


1 


4 


2 


1 


2 


4 


4 


3 


6 


2 


1 


3G 


27.5 


0-1 


9 


8 


5 


6 


6 


7 


8 


13 


9 


4 


11 


10 


96 


95 


1-2 


4 


6 


8 


3 


11 


14 


3 


3 


5 


3 


9 


6 


75 


68 


2-3 


3 


7 


4 


8 


4 


3 


6 


G 


4 


6 


1 


3 


55 


54 


3-4 


4 


5 


3 


6 


4 


4 


4 


3 


6 


3 


2 


5 


49 


48.5 


4-5 


1 


1 


5 


1 


2 


— 


2 


1 


1 


2 


— 


2 


18 


24 


Over 5 


4 


— 


2 


4 


3 


— 


4 


1 


2 


7 


5 


3 


35 


34.5 


Days per 


31 


23 


31 


30 


31 


30 


31 


31 


30 


31 


30 


30 


364 


351.5 


month 































EAINFALL 

The annual rainfall of Morococha is as follows : 

1906 28 inches ( 712 mm.) 

1907 40 " (1,011mm.) 

" 1908 57 " (1,450 mm.) 

1909 45 " (1,156 mm.) 

1910 47 " (1,195 mm.) 

1911 25 " ( 622 mm.) 

'"This figure is appro.ximate : some days' records were missing from the first 
three months of the year and the total was estimated on a proportional basis. 



174 



THE ANDES OF SOUTHERN PERU 






1. 




1 


r 




1 ? 


ij_j 












— 






— 




= 


= 



So 


1 




1 


1 
















iinr 











■NVf 
























5 




iinr 












~ 


^ 






•NVT 


1 


■ 








Ainr 








■Nrr 


i 












iinr 




























s 






A-inf 


















i 














janr 
























s? 










Ainr 


5: 


3 ; 




t 


> ' 




. d 








o 

■g 



to 







E 


•0 


tTY3W 


d 


C5 




o< 


II6I 





a 


s 


0I6I 


^^ 


00 


6061 









806 1 


3 


C5 




ioei 

9061 


fa 




- 



ci O 



«»«. 


frt 










p 


ci 


s 


h 


g 


s 






t». 


El 


c 




ii\ 


■a 


s 


13 




lA 






5 


■3 


to 

a 


3 
B 


i~> 


c3 










-3 

















rt 





c 


1^ 















C3 


tJO 


TS 


•3 


cn 





.i" i 



lis 

T ^ 

"a 



8 



S 
^ 



METEOROLOGICAL RECORDS 175 

The mean for the above six years amounts to 40 inches (1,024 
mm .). This is a value considerably higher than that for Cayl- 
loma or Santa Lucia. The greater rainfall of Morococha is prob- 
ably due in part to its more northerly situation. An abnormal 
feature of the rainfall of 1908, the rainiest year, is the large 
amount that fell in June. Ordinarily June and July, the coldest 
months, are nearly or quite rainless. The normal concurrence 
of highest temperatures and greatest precipitation is of course 
highly favorable to the plant life of these great altitudes. Full 
advantage can be taken of the low summer temperatures if the 
growing temperatures are concentrated and are accompanied by 
abundant rains. Since low temperatures mean physiologic dry- 
ness, whether or not rains are abundant, the dryness of the winter 
months has little effect in restricting the range of Alpine species. 

The seasonal distribution of rain helps the plateau people as 
well as the plateau plants. The transportation methods are 
primitive and the trails mere tracks that follow the natural lines 
of topography and drainage. Coca is widely distributed, likewise 
corn and barley which grow at higher elevations, and wool must 
be carried doAvn to the markets from high-level pastures. In the 
season of rains the trails are excessively wet and slippery, the 
streams are often in flood and the rains frequent and prolonged. 
On the other hand the insignificant showers of the dry or non- 
growing season permit the various products to be exchanged 
over dry trails. 

The activities of the plateau people have had a seasonal expres- 
sion from early times. Inca chronology counted the beginning of 
the year from the middle of May, that is when the dry season was 
well started and it was inaugurated with the festivals of the Sun. 
With the exception of June when the people were entirely busied 
in the irrigation of their fields, each month had its appropriate 
feasts until January, during which month and February and 
March no feasts were held. April, the harvest month, marked the 
recommencement of ceremonial observances and a revival of social 
life." 

" Christoval de Molina, The Fables and Rites of the Yncas, Hakluyt See. Pubis., lat 
Ser., No. 48, 1873. 



176 THE ANDES OF SOUTHERN PERU 

In Spanish times the ritualistic festivals, incorporated with 
fairs, followed the seasonal movement. Today progress in trans- 
portation has caused the decadence of many of the fairs but others- 
still survive. Thus two of the most famous fairs of the last cen- 
tury, those of Vilque (province of Puno) and Yunguyo (province 
of Chucuito), were held at the end of May and the middle of 
August respectively. Copacavaua, the famous shrine on the 
shores of Titicaca, still has a well-attended August fair and 
Huari, in the heart of the Bolivian plateau, has an Easter fair 
celebrated throughout the Andes. 

COCHABAMBA 

Cochabamba, Bolivia, lies 8,000 feet above sea level in a broad 
basin in the Eastern Andes. The Cerro de Tunari, on the north- 
west, has a snow and ice cover for part of the year. The tropical 
forests lie only a single long day's journey to the northeast. Yet 
the basin is dry on account of an eastern front range that keeps 
out the rain-bearing trade winds. The Eio Grande has here cut 
a deep valley by a roundabout course from the mountains to the 
plains so that access to the region is over bordering elevations. 
The basin is chiefly of structural origin. 

The weather records from Cochabamba are very important. I 
could obtain none but temperature data and they are complete for 
1906 only. Data for 1882-85 were secured by von Boeck " and they 
have been quoted by Sievers and Hann. The mean annual tem- 
perature for 1906 was 61.9° F. (16.6° C), a figure in close agree- 
ment with von Boeck's mean of 60.8° F. (16° C). The monthly 
means indicate a level of temperature favorable to agriculture. 
The basin is in fact the most fertile and highly cultivated area of 
its kind in Bolivia. Bananas, as well as many other tropical and 
subtropical plants, grow in the central plaza. The nights of mid- 
winter are uncomfortably cool; and the days of midsummer are 



'■' See Meteorologisehe Zeitschrift, Vol. 5, p. 195, 188S. Also cited by J. Hann in 
Handbuch der Climatologie, Vol. 2, Stuttgart, 1897; W. Sievers, Siid- und Mittelamerika, 
Leipzig and Vienna, 1914, p. 334. 



E, cochJ 










































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[JLY 










N( 


J)V. 










„ °f^- 






■80 
•70 
60 

■50 








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1 

URE, COCHABAMBA, 1907 




F 




* 


RIL 










M 


A.Y 










JUNE 1 






o 

20 

O 

-10 


























































^'• 


\ m 










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/\ 


r 


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/ 




w^ 


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f — 
































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C 




























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N( 


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X. 






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20 



10 


\ 








































A 




A /I 






















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\ 


, / 


V , 


A VI , 


I A 






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// 












\, 


\/ 


/ 


u 


TT 


/ 


\ 


A, 


A 


\/ 


r 


I 


A 


A 






\ 


V 


\/ 




/ 


/ 


\ 


/ ^ 


/ 


V 


/ 


\. 


' V 


i / 1 


A 








V 




/ 






V 




I 


/ 








V 






















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-4^ 
































^ 


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[AB, 


f 































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10" 



i OY 



,A/\ 



\^/ 



NOV. 



DEO 



^AA^JMAir 



c. 
ha" 

0° 



':G. 1081 108 F - MONTHLY MEANS OF DIURNAL RANGE, COCHABAMBA 



fx 


M. ; 


M. 


A. 


M. 


J. 


J. 


A. 


S. 


0. 


N. 


D. 


J. 


R 


M. 


A. 


M. 


J. 


C!.^ 












1906 




















1907 






10° 


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^' 






















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^ 






\ r'^-^, — 
























, 


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1 

1 


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,^ 


































o 

■5 


- 








































































/ 



































































































FIG 


. 108 A - 


-DIURNAL TEMPERATURE 


, COCHABAMBA 


1906 






























































• 


80 


i kfjl 




J^ 


.N. 










FEB, 










MARCH 

— K 










APRIL 










MAY 










JUjNE 










JULY 






- 


_ 






\UG 













SEPT. 











OCT 








"V- 


-7V 


NOV. 








^/ 


DEC. 






so 




26- 


70 
fiO 


VAji- 


/-s 


A^ 


„r 


^ 


7^ 


^/) 


t? 


^ 


-v^ 


^^^ 


■>7 


^^1 


V 


^ 


^ 




■^ 




^ 


- / 


^-V^ 




A>J 


^ 


- 




f\ 


















-^ 






^y^/' V/" 




"P 


^ 


7- 


=^ 




^7i 


'\^ 


-y= 


^ 


X7^ 


^'v 


^ 




r 


^/^^-SjC\ 


^N 


-^S2^ 


^-^^ 


Z^M-l 


70 



(iO 


^ 


20- 

IG- 


Mi' 


iimur 


^X 


\y 


'f^^ 


-^ 




V-'"" 




''"*^'* 


-V 




v-> •' 




^"~j 


~^'"' 








,-- , 






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^ 


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^' 


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V^ 


K 


\f 




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7^ 


s/ 


% 


17^- 


\ 


7^ 




y\ .'■ 


V ■- 


— V— 


.-,- 


t 




v''— 


--''V 


-'" 


A 


■«/ ? 






/ 


'v' 


A^ 




K 




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sr, 


16° 











' S' 




— ^ 


y — 


^^ 






^.*; 
















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-V 


— • 


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::x 


— ^/ 


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— -^<r 


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^ 


, / 


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-/ 


\ 






/. 


— ,1 


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.;r^ 


A 


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vr 


"^ 




\ 








— V 


1 




v--^ 


















^ 


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rv 


^ 


4C 




40 




















































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10 












































































^ 




'-i 




\ y 




'«• 


_ 


- 






















- 






































•6° 























FIG. 108 B 


- DIURNAL TEMPERATURE, COCHABAMBA 


, 1907 






















F. 




1 


J^ 


iN. 










F 


!B. 










MARCH 










APRIL 










MAY 










JUNE 






8C 


ii-' 


t-^'/feid 


um 














_> 




K 


— 71 




^ 








^ 






— 






























20.' 


V^ 


hvi 


y- 


^\ 


^ 


"1 fl 


r^ 


^"^ 


^— 


N^ 






V 














S,x^ 






v'"vj^yv 


^ 


-..-/• 


^r- 






^ A 








o W'^*^ 




VT/ 


^^ 


*s ■ 


-,^^ 


/^ 


^^.^'^ 


-r- 


r^^*^ 


.J's 


I-/' 




^ V 


'^^ — 




/ — 




-^v' 


-'"^^ 




.^-^J 


^, ^ 


"■^-^ 














" 










IS" 


'"^l7=\7 


\ ' 


-' . 








' 


A._J 


\ ,..■' 





... 


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'...., 






.. 


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...■•-■. 


A- 


■\ 


',_ 








'- 


■" 


'■-■f-. .,- 


--. 






-s 








BO 

40 


,, 


° W inim 


im 








' 










' 




' 


' 












\ 


„''"v 




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V 


- ^ 




\ 




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---' 




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J 


lUI) 




























































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.— - 




.'— 


6° 4 


o 






















































' 




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' 




v 






























































1 — 











c. c. 

■26° 

■2»° 10) 

-15° 

■10° 



FIG. 108 E -DIURNAL RANGE OF TEMPERATURE, COCHABAMBA, 1907 



i 



g? 



JAN. 




s 



^ 




MARCH 



g^ 




APRIL 



S4 



B 



^? 



M 



EZ 



JUf4E 



























































PIG. 108 D 


- DIURNAL RANGE OF TEMPERATURI 


:;, COCHABAMBA, 1906 




















































h 


C 




o\ 




J, 


^N. 










!•' 


JB. 










MAI 


tCH 










APpiL 










MAY 


L-A 






-^ 


JU^E 




-^ 




A 


JULY 








tA 


AUU 


i\ — 




-- 






SEP' 

n 


'• 


~^ — 






OCT 












(hi 










DEC. 








„ 2 
10 ■ 


•^ 


tA 


^ 


^^ 


t 


^1 


5 




A^ 


y4 








A^ 


t^ 


-^ 


^ 


n 


'"^ 


^ 


V/i 


Af^ 


rY^-^^TV 


^ 


Af^ 


J 


P 


± 


h 


v/- 


Y 


^ 


y 


^ 


— 1 




r-^'' 


VA 


h 


\/ 


w 


Vs 


l[ 


\a 


f^ 


-/^ 


^ 


^^m 


th 


^ 


p 


pw 


y 


p^N 


ij 


1 20 

1 '^ 


5-' 


o 






-^ 


^ 


^ 






i 






/_V- 


-v 


"^ 


^~i 


^ 


i- 




i — 1 






^ 




/ — 








— V- 








-V- 




4 








-V 








r 












i- 




— - 










— h 


--V-n 














1/ 










—\ 










1 ' 


"5 
























































































































































































































































— - 















































- 

























































FIG 


. 108 G - 


- DIURNAL ■> 


/AR 


lAB 


LIT 


Y, COCHABAMBA, 1906 


























































JAN. 








A 


FEB. 










MARCH 










AP 


IIL 










MiiY 
1 










JUNE 










JULY 












AUG 












SEP' 












OCT 










NOV 




Mr 




DEC. 






0^ 


w 


^aV- 


y^ 


\/^ 


y\ 


k 


.^^V. 


'^ 


r- 


\A. 


I A. 


^A^J 


sr 


^ 


^>/^ 


/^ 


\^ 


[^^^I^-AA^ 


vaAA^ 


.j^i^^y^^^:^.^ 


. /vI/\/^ 


^\J'\y4H^.^^L^\. 


/N./U- 


-^ 


/V vMv^ A IHAa Wv/WlV. ■ 


^:^VV^II 



FIG. 108 H - DIURNAL VARIABILITY, COCHABAMBA, 1907 



JAN. 



FEB. 



.aW^wVA 



MARCH 



A lA-v 



APRIL 



K^/K 



JUNE 







FIG 


108 C- 


MEAN MONTHLY TEMPERATURES, 


COCHABAMBA 










































J. F. 
— MJXiniiXi 


M. 


A. 


M. 


J. 


J. 


A. 


s. 


0. 


N. 


U. 


J. 


F. 


M. 


A. 


M. 


J. 





^i^ 






1906 






















1907 






Mi 


-an 




^-J 




J 


^ 





















_" " 


o 


^ 


— .. 


^^^ 










^''~' 













— - 


— 








..- 




'--., 


.. 






y 










— 












^"^ 


^ 





M nimu 


n 


'- 










■ 
















--, 










































40°- 







































FIG. 108 F - MONTHLY MEANS OF DIURNAL RANGE, COCHABAMBA 



K 


1 1 

J. 


F. 


M. 


A. 


M. 


J. 


1 1 

J. 


A. 


S. 


0. 


N. 


D. 


J. 


F. 


M. 


A. 


M. 


J. 


0> 


o 












1(1(16 




















1907 




, 








































^ 












. 


--^ 






















_ 


^ 








\ 






^ 























— 


■ ■ \ 














y 


































,o 




\-> 


































6 

















































































METEOROLOGICAL RECORDS 



177 



uncomfortably hot but otherwise the temperatures are delightful. 
The absolute extremes for 1906 were 81.5° F. (27.5° C.) on Decem- 
ber 11, and 39.9° F. (4.4° C.) on July 15 and 16. The (uncor- 
rected) readings of von Boeck give a greater range. High minima 
rather than high maxima characterize the summer. The curve for 
1906 shows the maxima for June and July cut off strikingly by an 
abrupt drop of the temperature and indicates a rather close re- 
striction of the depth of the season to these two months, which are 
also those of greatest diurnal range. 

The rainfall of about 18 inches is concentrated in the summer 
season, 85 per cent falling between November and March. Dur- 
ing this time the town is somewhat isolated by swollen streams 
and washed out trails : hence here, as on the plateau, there is a dis- 
tinct seasonal distribution of the work of planting, harvesting, 
moving goods, and even mining, and of the general commerce of 
the to-wns. There is an approach to our winter season in this re- 
spect and in respect of a respite from the almost continuously 
high temperatures of summer. The daytime temperatures of sum- 
mer are however mitigated by the drainage of cool air from the 
surrounding highlands. This, indeed, prolongs the period re- 
quired for the maturing of plants, but there are no harmful results 
because freezing temperatures are not reached, even in winter. 



MONTHLY TEMPEEATTJEES, COCHABAMBA, 1906 



January . , 
February . 
March ... 
April .... 

May 

June 

July 

August . . . 
September 
October . . 
November 
December 



Mean Min. 



55.7 
61.2 

59.8 

55.06 

50.9 

47.1 

44.8 

49.9 

55.6 

56.1 

58.1 

58.6 



Mean Max. 



72.25 

71.3 

72.6 

70.8 

68.7 

65.6 

64.9 

68.0 

73.2 

73.4 

75.7 

73.9 



Mean Range 



16.65 
10.1 

12.8 

15.74 

17.8 

18.5 

20.1 

18.1 

17.6 

17.3 

17.6 

15.3 



Daily Mean 



63.3 
65.5 
65.5 
62.2 
59.1 
55.6 
54.1 
58.2 
63.7 
64.0 
66.2 
65.8 



178 



THE ANDES OF SOUTHERN PERU 



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Fig. 114. 











/ \ 










( 




Nor 


nal Curv 


>i 

1 


CLOt 


JDS 
/ 


^ 
















1 

1 1 
1 1 


x> 


J 


\ 
















i 1 

I 1 
1 1 
t 1 




\ 
















1 




\ 










f^n° 


Dry 


/ 






\ 




















^ 


V^ 






— 








j \. 






\ 










Wet 


Bulb 


/ 




\ 




\ 
















"■■-,. 
































6< 


,.m. 


Nc 


on 




6p 


.m. 


Mi 


dt. 





c. 



20 



15 



Fig. 115. 



Fig. 114 — Typical afternoon cloud composition at Santa Ana during the dry season. 

Fig. 115 — Temperature curve for Abancay drawn from data obtained by hourly 
readings on September 27, 1911. Dry bulb readings are shown by a heavy solid 
line, wet bulb readings by a dotted line. The heavy broken line shows the normal 
curve when the sky is unobscured by cloud. The reduction in temperature with cloud 
is very marked. 



METEOROLOGICAL RECORDS 179 

FBEQUENCY OF DIXJRNAX, VABIABILITY AT COCHABAMBA, 1906 



Degrees F. 


J. 


p. 


M. 


A. 


M. 


J. 


J. 


A. 


s. 


0. 


N. 


D. 


Total No, of 
days 





1 


3 


10 


12 


6 


10 


9 


6 


9 


6 


3 


4 


79 


0-1 


5 


— 


3 


5 


3 


3 


— 


4 


— 


3 


1 


1 


28 


1-2 


10 


10 


13 


11 


15 


7 


14 


11 


15 


10 


14 


13 


143 


2-3 


7 


11 


3 


1 


5 


8 


7 


4 


3 


6 


7 


6 


68 


3-4 


6 


2 


2 


1 


2 


2 


1 


6 


3 


4 


3 


5 


37 


4-5 


— 


— 


— 


— 


— 


• — 


— 


— 


— 


1 


1 


1 


3 


Over 5 


2 


2 


— 


— 


— 


— 


— 


— 


— 


1 


1 


1 


7 



A series of curves shows the daily inarch of temperature at 
various locations along the seventy-third meridian. Figs. 109 to 
113 are for the Urubamba Valley. Eespectively they relate to 
Pongo de Mainique, 1,200 feet elevation (365 m.), the gateway to 
the eastern plains; Yavero, 1,600 feet (488 m.), where the tribu- 
tary of this name enters the main stream; Santo Anato 1,900 feet 
(580 m.) ; Saliuayaco, 2,400 feet (731 m.), and Santa Ana, 3,400 
feet (1,036 m.), one of the outposts of civilization beyond the East- 
ern Cordillera. The meteorological conditions shown are all on 
the same order. They are typical of dry season weather on the 
dry floor of a montaiia valley. The smooth curves of clear days 
are marked by high mid-day temperatures and great diurnal 
range. Santo Anato is a particularly good illustration : the range 
for the 24 hours is 38° F. (21.1° C). This site, too, is remarkable 
as one of the most unhealthful of the entire valley. The walls of 
the valley here make a sharp turn and free ventilation of the 
valley is obstructed. During the wet season tertian fever pre- 
vails to a degree little known east of the Cordillera, though 
notorious enough in the deep valleys of the plateau. The curves 
show relative humidity falling to a very low minimum on clear 
days. At Santo Anato and Santa Ana, for example, it drops 
below 30 per cent during the heat of the day. Afternoon cloudi- 
ness, however, is a common feature even of the dry season. 
A typical afternoon cloud formation is shown in Fig. 114. The 
effect on temperature is most marked. It is well shown in the 
curve for August 20 and 22 at Yavero. Cloudiness and precipita- 



180 



THE ANDES OF SOUTHERN PERU 





ClAuds.lCool 


Wink 






Clouds Sun j Ha^I ami Snow 






S.iua 


1 fruni Easi 


. Ha 


1 


r, 


F. 






















Thu 


ider 


torn 


1 










/. 


i 

now- 


:-IUi 


1 


15 




















,. 


















/ 








A 


Y 




























/ 














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r 


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o 




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n 












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, 










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[)ry B 


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lb • 


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1 .' 








. 




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1 
1 
























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-B* 














s 


/ 































































































































Noon 6 p.m. Midt. 6 a.m. Noon 6 p.m. Midt. 6 a.m. Noon 6 p.m. 

Fig. 116. 



F. 




Haze 


Clear 


Haze 






c. 






1 


/\ 


\ 












(^ 




~\ 












\ 




\ 
















\ 


















\, 








/ 








\ 




















-15 


























































































■\ 










/ 








••,,. 







































BO- 



40- 



6 a.m. Noon 6 p.m. Midt. 

Fig. 117. 



No W 



6 a.m. Noon C p.m. Midt. 6 a.m. 
FlQ. 118. 



Figs. 116-118 — Temperature curves for locations in the Maritime Cordillera and 
its western valleys, October, 1911. For construction of curves see Figs. 
109-113. Fig. 116 is for Camp 13 on the northern slope of the Maritime Cordillera 
(which here runs from east to west), October 13-15; Fig. 117 for Cotahuasi, October 
26; Fig. 118 for Salamanca, October 31. 

tion increase during the summer months. At Santa Ana the 
rainfall for the year 1894-95 amounted to 50 inches, of which 60 
jper cent fell between December and March. For a discussion of 



METEOROLOGICAL RECORDS 



181 



topographic features that have some highly interesting climatic 
effects in the eastern valleys of Peru see Chapter VI. 

Abancay, 8,000 feet (2,440 m.), in one of the inter- Andean 
basins, is situated in the zone of marked seasonal precipitation. 




F. 



70- 



Noon 6 p.m. Midt. 6 a.m. 

Fig. 119. 



avier Wind 
.(LGloud— 



^0 



MS" 



6 a.m. Noon 6 p.m. Midt. G a.m. 
FlQ. 120. 



Figs. 119-120 — Temperature curves for the Coast Desert, November, 1911. Fig. 
119 is for Aplao, November 4 and 5; and Fig. 120 for Camana, November 9 and 10. 
For construction of curves see Figs. 109 to 113. 

The single day's record shows the characteristic effect of cloud 
reducing the maximum temperature of the day and maintaining 
the relative humidity. 

Camp 13, 15,400 feet (4,720 m.), lies near the crest of the Mari- 
time Cordillera a little south of Antabamba. Afternoon storms 
are one of its most significant features. Cotahuasi, 9,100 feet 
(2,775 m.) is near the head of a west-coast valley. Its low humid- 
ity is worthy of note. That for Salamanca, 12,700 feet (3,870 m.), 
is similar but not so marked. 

Aplao, 3,100 feet (945 m.), and Camana at the seacoast are 
stations in the west-coast desert. The interior location of the 
former gives it a greater range of temperature than Camana, yet 
even here the range is small in comparison with the diurnal ex- 
tremes of the montana, and the tempering effect of the sea-breeze 
is clearly apparent. Camana shows a diurnal temperature range 
of under 10° F. and also the high relative humidity, over 70 per 
cent, characteristic of the coast. 



PART II 
PHYSIOGRAPHY OF THE PERUVIAN ANDES 

CHAPTER XI 
THE PERUVIAN LANDSCAPE 

From the Avest coast the great Andean Cordillera appears to 
have little of the regularity suggested by our relief maps. Steep 
and high cliffs in many places form the border of the land and 
obstruct the view; beyond them appear distant summits rising into 
the zone of clouds. Where the cliffs are absent or low, one may 
look across a sun-baked, yellow landscape, generally broken by ir- 
regular foothills that in turn merge into the massive outer spurs 
and ranges of the mountain zone. The plain is interrupted by 
widely separated valleys whose green lowland meadows form a 
brilliant contrast to the monotonous browns and yellows of the 
shimmering desert. In rare situations the valley trenches enable 
one to look far into the Cordillera and to catch memorable 
glimpses of lofty peaks capped with snow. 

If the traveler come to the west-coast landscape from the well- 
molded English hills or the subdued mountains of Vermont and 
New Hampshire with their artistic blending of moderate profiles, 
he will at first see nothing but disorder. The scenery will be im- 
pressive and, in places, extraordinary, but it is apparently com- 
posed of elements of the greatest diversity. All the conceivable 
variations of form and color are expressed, with a predominance 
of bold rugged aspects that give a majestic appearance to the 
mountain-bordered shore. One looks in vain for some sign of a 
quiet view, for some uniformity of features, for some landscape 
that will remind him of the familiar hills of home. The Andes 
are aggressive mountains that front the sea in formidable spurs 
or desert ranges. Could we see in one view their entire elevation 

183 



184. THE ANDES OF SOUTHERN PERU 

from depths of over 20,000 feet beneath sea level to snowy sum- 
mits, a total altitude of 40,000 feet (12,200 m.), their excessive 
boldness Avould be more apparent. No other mountains in the 
world are at once so continuously lofty and so near a coast which 
drops off to abyssal depths. 

The view from the shore is, however, but one of many which 
the Andes exhibit. Seen from the base the towering ranges dis- 
play a stern aspect, but, like all mountains, their highest slopes 
and spurs must be crossed and re-crossed before the student is 
aware of other aspects of a quite ditferent nature. The Andes 
must be observed from at least three situations: from the floors 
of the deep intermontane valleys, from the intermediate slopes 
and summits, and from the uppermost levels as along the range 
crests and the highest passes. Strangely enough it is in the sum- 
mit views that one sees the softest forms. At elevations of 14,000 
to 16,000 feet (4,270 to 4,880 m.), where one Avould expect rugged 
spurs, serrate chains, and sharp needles and horns, one comes fre- 
quently upon slopes as well graded as those of a city park — grass- 
covered, waste-cloaked, and with gentle declivity (Figs. 121-124). 

The graded, waste-cloaked slopes of the higher levels are in- 
terpreted as the result of prolonged denudation in an erosion 
cycle which persisted through the greater part of the Tertiary 
period, and which was closed by uplifts aggregating at least sev- 
eral thousands of feet. Above the level of the mature slopes rise 
the ragged profiles and steejD, naked declivities of the snow-capped 
mountains which bear residual relations to the softer forms at 
their bases. They are formed upon rock masses of greater 
original elevation and of higher resistance to denudation. Though 
they are dominating topographic features, they are much less ex- 
tensive and significant than the tame landscape which they sur- 
mount. 

Below the level of the mature slopes are topographic features 
of equal prominence : gorges and canyons up to 7,000 feet deep. 
The deeply intrenched streams are broken by Avaterfalls and al- 
most continuous rapids, the valley walls are so abrupt that one 
may, in places, roll stones doA\m a 4,000-foot incline to the river 




Fig. 121. 




Fig. 122. 



Fig. 121 — ^Looking north from the hill near Anta in the Anta basin north of 
Cuzco. Typical composition of slopes and intermont basins in the Central Andes. 
Alluvial fill in the foreground; mature slopes in the background; in the extreme back- 
groimd the snow-capped crests of the Cordillera Vilcapampa. 

Fig. 122 — Showing topographic conditions before the formation of the deep canyons 
in the Maritime Cordillera. The view, looking across a tributary canyon of the 
Antabaraba river, shows in the background the main canj'on above Huadquirca. Com- 
pare with Fig. 60. 







8 ° 



2! - 




g a 

3 

p 



THE PERUVIAN LANDSCAPE 



185 




bed, and the tortuous trail now follows a stream in the depths of 
a profound abyss, now scales the walls of a labyrinthine canyon. 

The most striking elements of scenery are not commonly the 
most important in physiography. The oldest and most significant 
surface may be at the top of the country, where it is not seen by 
the traveler or where it 
cannot impress him, ex- 
cept in contrast to fea- 
tures of greater height 
or color. The layman 
frequently seizes on a 
piece of bad-land erosion 
or an outcrop of bright- 
colored sandstone or a 
cliff of variegated clays or 
a snow-covered mountain as of most interest. All we can see 
of a beautiful snow-clad peak is mere entertainment compared 
with what subdued waste-cloaked hill-slopes may show. We do 
not wish to imply that everywhere the tops of the Andes are 
meadows, that there are no great scenic features in the Peruvian 
mountains, or that they are not worth while. But we do wish to 
say that the bold features are far less important in the interpre- 
tation of the landscape. 

Amid all the variable forms of the Peruvian Cordillera certain 
strongly developed types recur persistently. That their impor- 
tance and relation may be appreciated we shall at once name them 
categorically and represent them in the form of a block diagram 
(Fig. 126). The principal topographic types are as follows: 



Fig. 125 — Mature upper and young lower 
slopes at the outlet of the Cuzco basin. 



1. An extensive system of high-level, well-graded, mature slopes, below which 



2. Deep canyons with steep, and in places, cliffed sides and narrow floors, and 
above which are: 

3. Lofty residual mountains composed of resistant, highly deformed rock, now 
sculptured into a maze of serrate ridges and sharp commanding peaks. 

4. Among the forms of high importance, yet causally unrelated to the other 
closely associated types, are the volcanic cones and plateaus of the western Cordil- 
lera. 



186 



THE ANDES OF SOUTHERN PERU 



5. At tlie valley heads are a full complement of glacial features, such as cirques, 
hanging valleys, reversed slopes, terminal moraines, and valley trains. 

6. Finally there is in all the valley bottoms a deep alluvial fill formed during 
the glacial period and now in process of dissection. 

Thougli there are in many places special features either re- 
motely related or quite unrelated to the principal enumerated 
types, they belong to the class of minor forms to which relatively 
small attention will be paid, since they are in general of small ex- 
tent and of purely local interest. 

The block diagram represents all of these features, though of 




Fig. 126 — Block diagram of the typical physiographic features of the Peruvian 
Andes. 

necessity somewhat more closely associated than they occur in 
nature. Reference to the photographs. Figs. 121-12-4, will make it 
clear that the diagram is somewhat ideal: on the other hand the 
photographs together include all the features which the diagram 
displays. In descending from any of the higher passes to the val- 
ley floor one passes in succession down a steep, well-like cirque at 
a glaciated valley head, across a rocky terminal moraine, then 
down a stair-like trail cut into the steep scarps which everywhere 
mark the descent to the main valley floors, over one after another 
of the confluent alluvial fans that together constitute a large part 
of the valley fill, and finally down the steep sides of the inner val- 
ley to the boulder-strewn bed of the ungraded river. 



THE PERUVIAN LANDSCAPE 187 

We shall now turn to eacli group of features for description 
and explanation, selecting for first consideration the forms of 
widest development and greatest significance — the high-level ma- 
ture slopes lying between the lofty mountains which rise above 
them and the deep, steep-walled valleys sunk far below them. 
These are the great pasture lands of the Cordillera; their higher 
portions constitute the typical i^una of the Indian shepherds. In 
many sections it is possible to pasture the vagrant flocks almost 
anywhere upon the graded slopes, confident that the ichu, a 
tufted forage grass, will not fail and that scattered brooks and 
springs will supply the necessary water. At nightfall the flocks 
are driven down between the sheltering walls of a canyon or in 
the lee of a cliff near the base of a mountain, or, failing to reach 
either of these camps, the shepherd confines his charge within the 
stone walls of an isolated corral. 

In those places where the graded soil-covered slopes lie within 
the zone of agriculture — below 14,000 feet — they are cultivated, 
and if the soil be deep and fertile they are very intensively culti- 
vated. Between Anta and Urubamba, a day's march north of 
Cuzco, the hill slopes are covered with wheat and barley fields 
which extend right up to the summits (Fig. 134). In contrast are 
the uncultivated soil-less slopes of the mountains and the bare val- 
ley walls of the deeply intrenched streams. The distribution of 
the fields thus brings out strongly the principal topographic rela- 
tions. Where the softer slopes are at too high a level, the climatic 
conditions are extreme and man is confined to the valley floors 
and lower slopes where a laborious system of terracing is the first 
requirement of agriculture. 

The appearance of the country after the mature slopes had 
been formed is brought out in Fig. 122. The camera is placed on 
the floor of a still undissected, mature valley which shows in the 
foreground of the photograph. In the middle distance is a valley 
whose great depth and steepness are purposely hidden; beyond 
the valley are the smoothly graded, catenary curves, and inter- 
locking spurs of the mature upland. In imagination one sees the 
valleys filled and the valley slopes confluent on the former (now 



188 THE ANDES OF SOUTHERN PERU 

imaginary) valley floor Avliicli extends without important change 
of expression to the border of the Cordillera. No extensive cliffs 
occur on the restored surface, and none now occur on large tracts 
of the still undissected upland. Since the mature slopes represent 
a long period of weathering and erosion, their surfaces were cov- 
ered with a deep layer of soil. Where glaciation at the higher 
levels and vigorous erosion along the canyons have taken place, 
the former soil cover has been removed ; elsewhere it is an impor- 
tant feature. Its presence lends a marked softness and beauty to 
these lofty though subdued landscapes. 

The graded mountain slopes were not all developed (1) at the 
same elevation, nor (2) upon rock of the same resistance to de- 
nudation, nor (3) at the same distance from the major streams, 
nor (4) upon rock of the same structure. It follows that they will 
not all display precisely the same form. Upon the softer rocks at 
the lowest levels near the largest streams the surface was worn 
down to extremely moderate slopes with a local relief of not more 
than several hundred feet. Conversely, there are quite unreduced 
portions Avhose irregularities have mountainous proportions, and 
between these extremes are almost all possible variations. Though 
the term mature in a broad way expresses the stage of develop- 
ment which the land had reached, post mature should be applied 
to those portions which suffered the maximum reduction and now 
exhibit the softest profiles. At no place along the 73rd meridian 
was denudation carried to the point of even local peneplanation. 
All of the major and some of the minor divides bear residual ele- 
vations and even approximately plane surfaces do not exist. 

Among the most important features of the mature slopes are 
(1) their great areal extent — they are exhibited thi'bughout the 
whole Central Andes, (2) their persistent development upon rocks 
of whatever structure or degree of hardness, and (3) their pres- 
ent great elevation in spite of moderate grades indicative of their 
development at a much lower altitude. Mature slopes of equiva- 
lent form are developed in widely separated localities in the Cen- 
tral Andes : in every valley about Cochabamba, Bolivia, at 10,000 
feet (3,050 m.) ; at Crucero Alto in southern Peru at 14,600 feet 




5°20' 



72%0 



ENG.AND PTG.BY THE TOPOGHAPHIC ET/GRAVtNG GO. WASH.,D. C 

Edition of 1916. 



THE YALE J^RinrLAOS]" EXPEDITION OT 19U 

HIRAM BINGHAJl/t.DIRECTOB- 

COBXJPUHA OITADRANG-LE 

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THE PERUVIAN LANDSCAPE 





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Fig. 127 — Topographic profiles across typical valleys of southern Peru. They are 
drawn to scale and the equality of gradient of the gentler upper slopes is so close that 
almost any curve wouM serve as a composite of the whole. These curves form the 
basis of the diagram. Fig. 128, whereby the amount of elevation of the Andes in late 
geologic time may be determined. The approximate locations of the profiles are as 
follows: 1, Antabamba; 2, Chuquibambilla; 3, upland south of Antabamba; 4, Apurimae 
Canyon above Pasaje; 5, Abaneay; 6, Arma (Cordillera Vilcapampa) ; 7, divide above 
Huancarama; 8, Huascatay; 9, Huascatay, farther downstream; 10, Rio Pampas. The 
upper valley in 8 is still undisseeted; 7 is practically the same; 8a is at the level 
which 8 must reach before its side slopes are as gentle as at the end of the preceding 
interrupted cycle. 

(4,450 m.) ; several hundred miles farther north at Anta near 
Cuzco, 11,000 feet to 12,000 feet (3,600 to 3,940 m.), and Fig. 129 
shows typical conditions in the Vilcabamba Valley along the route 
of the Yale Peruvian Expedition of 1911. The characteristic 
slopes so clearly represented in these four photographs are the 
most persistent topographic elements in the physiography of the 
Central Andes. 



190 THE ANDES OF SOUTHERN PERU 

The rock masses upon which the mature slopes were formed 
range from soft to hard, from stratified shales, slates, sandstones, 
conglomerates, and limestones to volcanics and intrusive granites. 
While these variations impose corresponding differences of form, 
the graded quality of the slopes is rarely absent. In some places 
the highly inclined strata are shown thinly veiled with surface 
debris, yet so even as to appear artificially graded. The rock in 
one place is hard granite, in another a moderately hard series of 
lava flows, and again rather weak shales and sandstones. 

Proof of the rapid and great uplift of certain now lofty moun- 
tain ranges in late geologic time is one of the largest contribu- 
tions of physiography to geologic history. Its validity now rests 
upon a large body of diversified evidence. In 1907 I crossed the 
Cordillera Sillilica of Bolivia and northern Chile and came upon 
clear evidences of recent and great uplift. The conclusions pre- 
sented at that time were tested in the region studied in 1911, 500 
miles farther north, with the result that it is noAv possible to state 
more precisely the dates of origin of certain prominent topo- 
graphic forms, and to reconstruct the conditions which existed 
before the last great uplift in which the Central Andes were born. 
The relation to this general problem of the forms under discus- 
sion will now be considered. 

The gradients of the mature slopes, as we have already seen, 
are distinctly moderate. In the Anta region, over an area several 
hundred square miles in extent, they run from several degrees to 
20° or 30°. Ten-degree slopes are perhaps most common. If the 
now dissected slopes be reconstructed on the basis of many 
clinometer readings, photographs, and topographic maps, the re- 
sult is a series of profiles as in Fig. 127. If, further, the restored 
slopes be coordinated over an extensive area the gradients of the 
resulting valley floors will run from 3° to 10°. Finally, if these 
valley floors be extended westward to the Pacific and eastward 
to the Amazon basin, they will be found about 5,000 feet above 
sea level and 4,000 feet above the eastern plains. (For explana- 
tion of method and data employed, see the accompanying figures 
127-128). It is, therefore, a justifiable conclusion that since the 



THE PERUVIAN LANDSCAPE 



191 




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192 THE ANDES OF SOUTHERN PERU 

formation of the slopes the Andes have been uplifted at least a 
mile, or, to put it in another way, the Andes at the time of forma- 
tion of the mature slopes were at least a mile lower than they are 
at present. 

Further proof of recent and great uplift is afforded by the 
deeply intrenched streams. After descending the long graded 
slopes one comes upon the cliffed canyons with a feeling of con- 
sternation. The effect of powerful erosion, incident upon uplift, 
is heightened by the ungraded character of the river bed. Falls 
and rapids abound, the river profiles suggest tumultuous descents, 
and much time "will elapse before the river beds have the regular 
and moderate gradients of the streams draining the mature sur- 
face before uplift as sho^vn in the profiles by the dotted lines rep- 
resenting the restored valley floors of the older cycle. Since the 
smooth-contoured landscape was formed great changes have taken 
place. The streams have changed from completely graded to al- 
most completely ungraded profiles; in place of a subdued land- 
scape we now have upland slopes intersected by mile-deep can- 
yons; the high-level slopes could not have been foi-med under 
existing conditions, for they are being dissected by the present 
streams. 

Since the slopes of the land in general undergo progressive 
changes in the direction of flatter gradients during a given geo- 
graphical cycle, it follows that with the termination of one cycle 
and the beginning of another, two sets of slopes will exist and that 
the gradients of the two mil be unlike. The result is a break in 
the descent of the slopes from high to low levels to which the name 
"topographic unconformity" is now applied. It mil be a promi- 
nent feature of the landscape if the higher, older, and flatter gradi- 
ents have but little declivity, and the gradients of the lower 
younger slopes are very steep. In those places where the relief 
of the first cycle was still great at the time of uplift, the erosion 
forms of the second cycle may not be differentiated from those of 
the first, since both are marked by steep gradients. In the Cen- 
tral Andes the change in gradient between the higher and lower 
slopes is generally well marked. It occurs at variable heights 



72%o' 




14*50 



72%o' 



ENQ.AND PTG.BY THE TOPOGRAPHIC ENGRAVING CO. WASH.,D. C. 



i5"20' 



Edition of 1916. 



THE TALE PERUVIAN EXPEDITION OF 19IL 
HIRAM: BINGHAM, director 

cotahhasi quadrang-le 




Contoui* tntd'vttl30l>&ot- 



THE PERUVIAN LANDSCAPE 193 

above the valley floors, though rarely more than 3,000 feet above 
them. In the more central tracts, far from the main streams and 
their associated canyons, dissection in the present erosion cycle 
has not yet been initiated, the mature slopes are still intact-, and 
a topographic unconformity has not yet been developed. The 
higher slopes are faced with rock and topped with slowly moving 
waste. Ascent of the spur end is by steep zigzag trails ; once the 
top is gained the trail runs along the gentler slopes without spe- 
cial difficulties. 

It is worth noting at this point that the surface of erosion still 
older than the mature slopes lierewith described appears not to 
have been developed along the seventy-third meridian of Peru, or 
if developed at one time, fragments of it no longer remain. The 
last well-developed remnant is southwest of Cuzco, Fig. 130. I 
have elsewhere described the character and geographic distribu- 
tion of this oldest recognizable surface of the Central Andes. ^ 
Southern Peru and Bolivia and northern Chile display its features 
in what seems an unmistakable manner. The best locality yet found 
is in the Desaguadero Valley between Ancoaqui and Concordia. 
There one may see thousands of feet of strongly inclined sedi- 
ments of varying resistance beveled by a well-developed surface 
of erosion whose preserval is owing to a moderate rainfall and to 
location in an interior basin.^ 

The highest surface of a region, if formed during a prolonged 
period of erosion, becomes a surface of reference in the determina- 
tion of the character and amount of later crustal deformations, 
having somewhat the same functions as a key bed in stratigraphic 
geology. Indeed, concrete physiographic facts may be the only 
basis for arguments as to both epeirogenic and orogenic move- 
ments. The following considerations may show in condensed form 
the relative value of physiographic evidence : 

1. If movements in the earth's crust are predominantly doivn- 



^ The Physiography of the Central Andes, Am. Journ. Sci., Vol. 40, 1909, pp. 197-217 
and 373-402. 

' Results of an Expedition to the Central Andes, Bull. Am. Geog. See, Vol. 46, 1914. 
Figs. 28 and 29. 



194 THE ANDES OF SOUTHERN PERU 

ward, sedimentation may be carried on continuously and a clear 
geologic record may be made. 

2. Even if crustal movements are alternately downward and 
upward, satisfactory conclusions may be drawn from both (a) the 
nature of the buried surfaces of erosion, and (b) the alternating 
character of the sediments. 

3. If, however, the deformative processes effect steady or in- 
termittent uplifts, there may be no sediments, at least within the 
limits of the positive crustal units, and a geologic record must be 
derived not from sedimentary deposits but from topograjihic 
forms. We speak of the lost intervals represented by strati- 
graphic breaks or unconformities and commonly emphasize our 
ignorance concerning them. The longest, and, from the human 
standpoint, the most important, break in the sedimentary record 
is that of the present wherever degradation is the predominant 
physiographic process. Unlike the others the lost interval of the 
present is not lost, if we may so put it, but is in our possession, 
and may be definitely described as a concrete thing. It is the 
physiography of today. 

Even where long-buried surfaces of erosion are exposed to 
view, as in northern Wisconsin, where the Pre-Cambrian paleo- 
plain projects from beneath the Paleozoic sediments, or, as in New 
Jersey and southeastern Pennsylvania, where the surface devel- 
oped on the crystalline rocks became by depression the floor of the 
Triassic and by more recent uplift and erosion has been exposed 
to view, — even in such cases the exposures are of small extent and 
give us at best but meager records. In short, many of the breaks 
in the geologic record are of such long duration as to make im- 
perative the use of physiographic principles and methods. The 
great Appalachian System of eastern Noi'th America has been a 
land area practically since the end of the Paleozoic. In the Cen- 
tral Andes the "lost interval," from the standpoint of the sedi- 
mentary record, dates from the close of the Cretaceous, except in 
a few local intermont basins partially filled with Tertiary or 
Pleistocene deposits. Physiographic interpretations, therefore, 
serve the double purpose of supplying a part of the geologic rec- 



THE PERUVIAN LANDSCAPE 195 

ord while at the same time forming a basis for the scientific study 
of the surface distribution of living forms. 

The geologic dates of origin of the principal topographic forms 
of the Central Andes may be determined with a fair degree of 
accuracy. Geologic studies in Peru and Bolivia have emphasized 
the wide distribution of the Cretaceous formations. They consist 
principally of thick limestones above and sandstones and con- 
glomerates below, and thus represent extensive marine submer- 
gence of the earth's crust in the Cretaceous where now there are 
very lofty mountains. The Cretaceous deposits are everywhere 
strongly deformed or uplifted to a great height, and all have been 
deeply eroded. They were involved, together with other and much 
older sediments, in the erosion cycle which resulted in the devel- 
opment of the widely extended series of mature slopes already 
described. From low^ scattered island elevations projecting above 
sea level, as in the Cretaceous period, the Andes were transformed 
by compression and uplift to a rugged mountain belt subjected 
to deep and powerful erosion. The products of erosion were in 
part swept into the adjacent seas, in part accumulated on the 
floors of intermont basins, as in the great interior basins of Titi- 
caca and Poopo. 

Since the early Tertiary strata are themselves deformed from 
once simple and approximately horizontal structures and sub- 
jected to moderate tilting and faulting, it follows that mountain- 
making movements again affected the region during later Terti- 
ary. They did not, however, produce extreme effects. They did 
stimulate erosion and bring about a reorganization of all the 
slopes with respect to the new levels. . 

This agrees closely with a second line of evidence which rests 
upon an independent basis. The alluvial fill Avhich lies upon all the 
canyon and valley floors is of glacial origin, as sho"\ATi by its inter- 
locking relations with morainal deposits at the valley heads. It is 
now in process of dissection and since its deposition in the Pleis- 
tocene had been eroded on the average about 200 feet. Clearly, 
to form a 3,000-foot canyon in hard rock requires much more time 
than to deposit and again partially to excavate an alluvial fill sev- 



196 THE ANDES OF SOUTHERN PERU 

eral hundred feet deep. Moreover, the glacial material is coarse 
throughout, and was built up rapidly and dissected rapidly. In 
most cases, furthermore, coarse material at the bottom of the gla- 
cial series rests directly upon the rock of a narrow and ungraded 
valley floor. From these and allied facts it is concluded that there 
is no long time interval represented by the transitions from de- 
grading to aggrading processes and back again. The early Pleisto- 
cene, therefore, seems quite too short a period in Avliich to produce 
the bold forms and effect the deep erosion which marks the period 
between the close of the mature cycle and the beginnings of deposi- 
tion in the Pleistocene. 

The alternative conclusion is that the greater part of the canyon 
cutting was effected in the late Tertiary, and that it continued into 
the early Pleistocene until further erosion was halted by changed 
climatic conditions and the augmented delivery of land Avaste to 
all the streams. The final development of the well-graded high- 
level slopes is, therefore, closely confined to a small portion of the 
Tertiary. The closest estimate which the facts support appears 
to be Miocene or early Pliocene. It is clear, however, that only the 
culmination of the period can be definitely assigned. Erosion was 
in full progress at the close of the Cretaceous and by middle 
Tertiary had effected vast changes in the landscape. The Tertiary 
strata are marked by coarse basal deposit and by thin and very 
fine top deposits. Though their deformed condition indicates a 
period of crustal disturbance, the Tertiary beds give no indica- 
tion of wholesale transformations. They indicate chiefly tilting 
and moderate and normal faulting. The previously developed ef- 
fects of erosion were, therefore, not radically modified. The sur- 
face was thus in large measure prepared by erosion in the early 
Tertiary for its final condition of maturity reached during the 
early Pliocene. 

It seems appropriate, in concluding this chapter, to summarize 
in its main outlines the physiography of southern Peru, partly to 
condense the extended discussion of the preceding paragraphs, 
and partly to supply a background for the three chapters that 
follow. The outstanding features are broad plateau areas sepa- 



THE PERUVIAN LANDSCAPE 197 

rated by well-defined "Cordilleras." The plateau divisions are 
not everywhere of the same origin. Those southwest of Cuzco 
(Fig. 130), and in the Anta Basin (Fig. 124), northwest of Cuzco, 
are due to prolonged erosion and may be defined as peneplane 
surfaces uplifted to a great height. They are now bordered on 
the one hand by deep valleys and troughs and basins of erosion 
and deformation; and, on the other hand, by residual elevations 
that owe their present topography to glacial erosion superim- 
posed upon the normal erosion of the peneplane cycle. The 
residuals form true mountain chains like the Cordillera Vilcanota 
and Cordillera Vilcapampa; the depressions due to erosion or 
deformation or both are either basins like those of Anta and 
Cuzco or valleys of the canyon type like the Urubamba canyon; 
the plateaus are broad rolling surfaces, the punas of the Peruvian 
Andes. 

There are two other types of plateaus. The one represents a 
mature stage in the erosion cycle instead of an ultimate stage ; the 
other is volcanic in origin. The former is best developed about 
Antabamba (Figs. 122 and 123), where again deep canyons and 
residual ranges form the borders of the plateau remnants. The 
latter is well developed above Cotahuasi and in its simplest form 
is represented in Fig. 133. Its surface is the top of a vast accumu- 
lation of lavas in places over a mile thick. While rough in detail 
it is astonishingly smooth in a broad view (Fig. 29). Above it 
rise two types of elevations : first, isolated volcanic cones of great 
extent surrounded by huge lava flows of considerable relief; and 
second, discontinuous lines of peaks where volcanic cones of less 
extent are crowded closely together. The former type is displayed 
on the Coropuna Quadrangle, the latter on the Cotahuasi and La 
Cumbre Quadrangles. 

So high is the elevation of the lava plateau, so porous its soil, 
so dry the climate, that a few through-flowing streams gather the 
drainage of a vast territory and, as in the Grand Canyon country 
of our "West, they have at long intervals cut profound canyons. 
The Arma has cut a deep gorge at Salamanca ; the Cotahuasi runs 
in a canyon in places 7,000 feet deep ; the Majes heads at the edge 



198 THE ANDES OF SOUTHERN PERU 

of the volcanic field in a steep amphitheatre of majestic propor- 
tions. 

Finally, we have the plateaus of the coastal zone. These are 
plains with surfaces several thousand feet in elevation separated 
by gorges several thousand feet deep. The Pampa de Sihuas is an 
illustration. The post-maturely dissected Coast Eange separates 
it from the sea. The pampas are in general an aggradational 
product formed in a past age before uplift initiated the present 
canyon cycle of erosion. Other plateaus of the coastal zone are 
erosion surfaces. The Tablazo de lea appears to be of this type. 
That at Arica, Chile, near the southern boundary of Peru, is 
demonstrably of this type with a border on which marine plana- 
tion has in places given rise to a broad terrace effect.^ 

"The Physiography of the Central Andes, by Isaiah Bowman; Am. Journ. Sei., Vol. 
28, 1909, pp. 197-217 and 373-402. See especially, ibid., Fig. 11, p. 216. 




Fig. 129. 




Fig. 130. 



Fig. 129 — Composition of slopes at Puquiura, Vilcabamba Valley, elevation 9,000 
feet (2,740 m. ). The second prominent spur entering the valley on the left has a 
flattish top unrelated to the rock structure. Like tire spurs on the right its blunt end 
and flat top indicate an earlier erosion cycle at a lower elevation. 

Fig. 130 — Inclined Paleozoic strata truncated by an undulating surface of erosion 
at 15,000 feet, southwest of Cuzco. 




^ii-:-:.- '»■j_,^ ■■;,- ■■ . v::'?:¥*i,t., ... 




Fig. 131 — Terraced valley slopes at Huaynacotas, Cotaliuasi Valley, at ll.ridO feet 
(3,500 m.). Solimana is in the background. On the floor of the Cotixhuasi Canyon fruit 
trees grow. At Huaynacotas corn and potatoes are tlie chief products. The section is 
composed almost entirely of lava. There are over a hundred major Hows aggregating 
5,000 to 7,000 feet thick. 



CHAPTER Xn 

THE WESTERN ANDES: THE MARITIME CORDILLERA 
OR CORDILLERA OCCIDENTAL 

The Western or Maritime Cordillera of Peru forms part of 
the great volcanic field of South America which extends from 
Argentina to Ecuador. On the walls of the Cotahuasi Canyon 
(Fig. 131), there are exposed over one hundred separate lava 
flows pUed 7,000 feet deep. They overflowed a mountainous relief, 
completely burying a limestone range from 2,000 to 4,000 feet 
high. Finally, upon the surface of the lava plateau new moun- 
tains were formed, a belt of volcanoes 5,000 feet (1,520 m.) high 
and from 15,000 to 20,000 feet (4,570 to 6,100 m.) above the sea. 
There were vast mud flows, great showers of lapUli, dust, and 
ashes, and with these violent disturbances also came many changes 
in the drainage. Sixty miles northeast of Cotahuasi the outlet of 
an unnamed deep valley was blocked, a lake was formed, and sev- 
eral hundred feet of sediments were deposited. They are now 
wasting rapidly, for they lie in the zone of alternate freezing and 
thawing, a thousand feet and more below the snowline. Some of 
their bad-land forms look like the solid bastions of an ancient 
fortress, while others have the delicate beauty of a Japanese 
temple. 

Not all the striking effects of vulcanism belong to the remote 
geologic past. A day's journey northeast of Huaynacotas are a 
group of lakes only recently hemmed in by flows from the small 
craters thereabouts. The fires in some volcanic craters of the 
Peruvian Andes are still active, and there is no assurance that 
devastating flows may not again inundate the valleys. In the 
great Pacific zone or girdle of volcanoes the earth's crust is yet 
so unstable that earthquakes occur every year, and at intervals of 
a few years they have destructive force. Cotahuasi was greatly 
damaged in 1912; Abancay is shaken every few years; and the 
violent earthquakes of Cuzco and Arequipa are historic. 



200 THE ANDES OF SOUTHERN PERU 

On the eastern margin of the volcanic country the flows thin 
out and terminate on the summit of a limestone (Cretaceous) 
plateau. On the western margin they descend steeply to the nar- 
row west-coast desert. The greater part of the lava dips beneath 
the desert deposits; there are a few intercalated flows in the 
deposits themselves, and the youngest flows — limited in number — 
have extended down over the inner edge of the desert. 

The immediate coast of southern Peru is not volcanic. It is 
composed of a very hard and ancient granite-gneiss which forms 
a narrow coastal range (Fig. 171). It has been subjected to very 
long and continued erosion and now exhibits mature erosion forms 
of great uniformity of profile and declivity. 

From the outcrops of older rocks beneath the lavas it is pos- 
sible to restore in a measure the pre-volcanic topography of the 
Maritime Cordillera. In its present altitude it ranges from several 
thousand to 15,000 feet above sea level. The unburied topography 
has been smoothed out; the buried topography is rough (Figs. 29 
and 166). The contact lines between lavas and buried surfaces in 
the deep Majes and Cotahuasi valleys are in places excessively 
serrate. From this, it seems safe to conclude that the period of 
vulcanism was so prolonged that great changes in the unburied 
relief were effected by the agents of erosion. Thus, while the 
dominant process of volcanic upbuilding smoothed the former 
rough topography of the Maritime Cordillera, erosion likeAvise 
measurably smoothed the present high extra-volcanic relief in the 
central and eastern sections. The effect has been to develop a 
broad and sufficiently smooth aspect to the summit topography of 
the entire Andes to give them a plateau character. Afterward the 
whole mountain region was uplifted about a mile above its former 
level so that at present it is also continuously lofty. 

The zone of most intense volcanic action does not coincide with 
the highest part of the pre-volcanic topography. If the pre-vol- 
canic relief were even in a very general way like that which would 
be exhibited if the lavas were now removed, we should have to say 
that the chief volcanic outbursts took place on the western flank 
of an old and deeply dissected limestone range. 



WESTERN ANDES: MARITIME CORDILLERA 201 

The volume of the lavas is enormous. They are a mile and a 
half thick, nearly a hundred mUes wide, and of indefinite extent 
north and south. Their addition to the Andes, therefore, has 
greatly broadened the zone of lofty mountains. Their passes are 
from 2,000 to 3,000 feet higher than the passes of the eastern 
Andes. They have a much smaller number of valleys sufficiently 
deep to enjoy a mild climate. Their soil is far more porous and 
dry. Their vegetation is more scanty. They more than double 
the difficulties of transportation. And, finally, their all but un- 
populated loftier expanses are a great vacant barrier between 
farms in the warm valleys of eastern Peru and the ports on the 
west coast. 

The upbuilding process was not, of course, continuous. There 
were at times intervals of quiet, and some of them, were long 
enough to enable streams to become established. Buried valleys 
may be observed in a number of places on the canyon walls, where 
subsequently lava fiows displaced the streams and initiated new 
drainage systems. In these quiet intervals the weathering agents 
attacked the rock surfaces and formed soil. There were at least 
three or four such prolonged periods of weathering and erosion 
wherein a land surface was exposed for many thousands of years, 
stream systems organized, and a cultivable soil formed. No evi- 
dence has been found, however, that man was there to cultivate 
the soil. 

The older valleys cut in the quiet period are mere pygmies be- 
side the giant canyons of today. The present is the time of domi- 
nant erosion. The forces of vulcanism are at last relatively quiet. 
Eecent fiows have occurred, but they are limited in extent and in 
effects. They alter only the minor details of topography and 
drainage. Were it not for the oases set in the now deep-cut can- 
yon floors, the lava plateau of the Maritime Cordillera would 
probably be the greatest single tract of unoccupied volcanic coun- 
try in the world. 

The lava plateau has been dissected to a variable degree. Its 
high eastern margin is almost in its original condition. Its west- 
ern margin is only a hundred miles from the sea, so that the 



202 THE ANDES OF SOUTHERN PERU 

streams have steep gradients. In addition, it is lofty enough to 
have a moderate rainfall. It is, therefore, deeply and generally 
dissected. Within the borders of the plateau the degree of dissec- 
tion depends chiefly upon position with respect to the large 
streams. These were in turn located in an accidental manner. 
The repeated upbuilding of the surface by the extensive outflow 
of liquid rock obliterated all traces of the earlier drainage. In the 
Cotahuasi Canyon the existing stream, working do^vn through a 
mile of lavas, at last uncovered and cut straight across a moun- 
tain spur 2,000 feet high. Its course is at right angles to that 
pursued by the stream that once drained the spur. It is note- 
worthy that the Cotahuasi and adjacent streams take northerly 
courses and join Atlantic rivers. The older drainage was directly 
west to the Pacific. Thus, vulcanism not only broadened the 
Andes and increased their height, but also moved the continental 
divide still nearer the west coast. 

The glacial features of the western or Maritime Cordillera are 
of small extent, partly because vulcanism has added a considera- 
ble amount of material in post-glacial time, partly because the cli- 
mate is so exceedingly dry that the snowline lies near the top of 
the country. The slopes of the volcanic cones are for the most 
part deeply recessed on the southern or shady sides. Above 17,500 
feet (5,330 m.) the process of snow and ice excavation still con- 
tinues, but the tracts that exceed this elevation are confined to the 
loftiest peaks or their immediate neighborhood. There is a dis- 
tinct difference between the glacial forms of the eastern or moister 
and the western or dryer flanks of this Cordillera. Only peaks 
like Coropuna and Solimana near the western border now bear or 
ever bore snowfields and glaciers. By contrast the eastern aspect 
is heavily glaciated. On La Cumbre Quadrangle, there is a huge 
glacial trough at 16,000 feet (4,876 m.), and this extends with rami- 
fications up into the snowfields that formerly included the highest 
country. Prolonged glacial erosion produced a full set of topo- 
graphic forms characteristic of the work of Alpine glaciers. Thus, 
each of the main mountain chains that make up the Andean sys- 
tem has, like the system as a whole, a relatively more-dry and a 



72%0' 




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NQ.AND PTS.By THE TOPOGRAPHrc EIlGRAVING CO. WASH.,D. C. 

Edrtion a? i9I 



l^'so' 




"^S'^r^^f^P^ 



THE "ilALE PERUVIAN EICPEJJiTI' 

HIRAM BINGHAM, DIREC'r 

LA CUMBRE OUADBANG:_; 



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V 

I 











f 



:3;i 



'^i/mi 



(Cabtliiiost) 



WESTERN ANDES: MARITIME CORDILLERA 203 

relatively less-dry aspect. The snowline is, therefore, canted 
from west to east on each chain as well as on the system. How- 
ever, this effect is combined with a solar effect in an unequal way. 
In the driest places the solar factor is the more efficient and the 
snowline is there canted from north to south. 



CHAPTER XIII 

THE EASTERN ANDES: THE CORDILLERA VILCAPAAIPA 

The culminating range of the eastern Andes is the so-called 
Cordillera Vilcapampa. Its numerous, sharp, snow-covered peaks 
are visible in every summit view from the central portion of the 
Andean system almost to the western border of the Amazon basin. 
Though the range forms a water parting nearly five hundred miles 
long, it is crossed in several places by large streams that flow 
through deep canyons bordered by precipitous cliffs. The Uru- 
bamba between Torontoy and Colpani is the finest illustration. 
For height and ruggedness the Vilcapampa mountains are among 
the most noteworthy in Peru. Furthermore, they display glacial 
features on a scale unequaled elsewhere in South America north 
of the ice fields of Patagonia. 

GLACIERS AND GLACIAL FORMS 

One of the most impressive sights in South America is a 
tropical forest growing upon a glacial moraine. In many places 
in eastern Bolivia and Peru the glaciers of the Ice Age were from 
5 to 10 miles long — almost the size of the Mer de Glace or the 
famous Elione glacier. In the Juntas Valley in eastern Bolivia 
the tree line is at 10,000 feet (3,050 m.), but the terminal moraines 
lie several thousand feet lower. In eastern Peru the glaciers in 
many places extended down nearly to the tree line and in a few 
places well below it. In the Cordillera Vilcapampa vast snow- 
fields and glacier systems were spread out over a summit area 
as broad as the Southern Appalachians. The snowfields have 
since shrunk to the higher mountain recesses; the glaciers have 
retreated for the most part to the valley heads or the cirque 
floors; and the loAver limit of perpetual snow has been raised to 
15,500 feet. 

304 




Fig. 132. 




Fig. 133. 



Fig. 132 — Recessed volcanoes in the right background and eroded tuffs, ash beds, 
and lava flows on the left. Maritime Cordillera above Cotahuasi. 

Fig. 133 — The summit of the great lava plateau above Cotahuasi on the trail to 
Antabamba. The lavas are a mile and a half in thickness. The elevation is 16,000 
feet. Hence the volcanoes in the background, 17,000 feet above sea level, are mere 
hills on the surface of the lofty plateau. 




Fig. 134. 




Fig. 135. 



Fig. 134 — Southwestern aspect of the Cordillera Vilcapampa between Anta and 
Urubamba from Lake Huaipo. Rugged summit topography in the background, graded 
post-mature slopes in the middle distance, and solution lake in limestone in the fore- 
ground. 

Fig. 135 — Summit view, Cordillera Vilcapampa. There are fifteen glaciers repre- 
sented in this photograph. The camera stands on the summit of a minor divide in the 
zone of nivation. 



EASTERN ANDES: CORDILLERA VILCAPAMPA 205 

These features are surprising because neither Whymper ^ nor 
Wolf ^ mentions the former greater extent of the ice on the vol- 
canoes of Ecuador, only ten or twelve degrees farther north. 
Moreover, Eeiss ^ denies that the hypothesis of universal climatic 
change is supported by the facts of a limited glaciation in the 
High Andes of Ecuador ; and J. W. G-regory * completely overlooks 
published proof of the existence of former more extensive glaciers 
elsewhere in the Andes : 

"... the absence not only of any traces of former more ex- 
tensive glaciation from the tropics, as in the Andes and Kiliman- 
djaro, but also from the Cape." He says further: "In spite of 
the extensive glaciers now in existence on the higher peaks of the 
Andes, there is practically no evidence of their former greater 
extension." ( !) 

Whymper spent most of his time in exploring recent volcanoes 
oi- those recently in eruption, hence did not have the most favora- 
ble opportunities for gathering significant data. Eeiss was car- 
ried off his feet by the attractiveness of the hypothesis ^ relating 
to the effect of glacial denudation on the elevation of the snowline. 
Gregory appeared not to have recognized the work of Hettner on 
the Cordillera of Bogota and of Sievers ^ and Acosta on the Sierra 
Nevada de Santa Marta in northern Colombia. 

The importance of the glacial features of the Cordillera Vilca- 
pampa developed on a great scale in very low latitudes in the 
southern hemisphere is twofold: first, it bears on the still unset- 
tled problem of the universality of a colder climate in the Pleis- 
tocene, and, second, it supplies additional data on the relative de- 
pression of the snowline in glacial times in the tropics. Snow- 



' Travels Amongst the Great Andes of the Equator, 1892. 

^ Geografia y Geologia del Ecuador, 1892. 

" Das Hoehgebirge der Republik Ecuador, Vol. 2, 2 Ost-Cordillera, 1902, p. 162. 

* Contributions to the Geology of British East Africa; Pt. 1, The Glacial Geology 
of Mount Kenia, Quart. Journ. Geol. Soc, Vol. 50, 1894, p. 523. 

° See especially A. Penck {Penek and Bruckner), Die Alpen im Eiszeitalter, 1909, 
Vol. 1, p. 6, and I. C. Russell, Glaciers of Mount Rainier, 18th Ann. Rep't, U. S. Geol. 
Surv., 1896-97, Sect. 2, pp. 384-385. 

' Die Sierra Nevada de Santa Marta und die Sierra de PerijS, Zeitsehrift der 
Gesellschaft fur Erdkunde zu Berlin, Vol. 23, 1888, pp. 1-158. 



206 THE ANDES OF SOUTHERN PERU 

clad mountaiiis near the equator are really quite rare. Mount 
Kenia rising from a great jungle on the equator, Kilimandjaro 
with its two peaks, Kibo and Mawenzi, two hundred miles farther 
south, and Ingomwimbi in the Euwenzori group thirty miles north 
of the equator, are the chief African examples. A few mountains 
from the East Indies, such as Kinibalu in Borneo, latitude 6° north, 
have been found glaciated, though now without a snow cover. In 
higher latitudes evidences of an earlier extensive glaciation have 
been gathered chiefly from South America, whose extension 13° 
north and 56° south of the equator, combined with the great height 
of its dominating Cordillera, give it unrivaled distinction in the 
study of mountain glaciation in the tropics. 

Furthermore, mountain summits in tropical lands are delicate 
climatic registers. In this respect they compare favorably with 
the inclosed basins of arid regions, where changes in climate are 
clearly recorded in shoreline phenomena of a familiar kind. Lofty 
mountains in the tropics are in a sense inverted basins, the lower 
snowline of the past is like the higher shoreline of an interior 
basin ; the terminal moraines and the alluvial fans in front of them 
are like the alluvial fans above the highest strandline ; the present 
snow cover is restricted to mountain summits of small areal ex- 
tent, just as the present water bodies are restricted to the lowest 
portions of the interior basin; and successive retreatal stages are 
marked by terminal moraines in the one case as they are marked 
in the other by flights of terraces and beach ridges. 

I made only a rapid reconnaissance across the Cordillera Vilca- 
pampa in the winter season, and cannot pretend from my limited 
observations to solve many of the problems of the field. The data 
are incorporated chiefly in the chapter on Glacial Features. 
In this place it is proposed to describe only the more prominent 
glacial features, leaving to later expeditions the detailed descrip- 
tions upon which the solution of some of the larger problems must 
. depend. 

At Choquetira three prominent stages in the retreat of the ice 
are recorded. The lowermost stage is represented by the great fill 
of morainic and outwash material at the junction of the Cheque- 



EASTERN ANDES: CORDILLERA VILCAPAMPA 



207 



tira, and an unnamed valley farther south at an elevation of 
11,500 feet (3,500 m.)- -^ ^^^ below Choquetira a second moraine 
appears, elevation 12,000 feet (3,658 m.), and immediately above 
the village a third at 12,800 (3,900 m.). The lowermost moraine 
is well dissected, the second is ravined and broken but topo- 
graphically distinct, the third is sharp-crested and regular. A 
fourth though minor stage is represented by the moraine at the 
snout of the living glacier 
and still less important 
phases are represented in 
some valleys — possibly the 
record of post-glacial 
changes of climate. Each 
main moraine is marked by 
an important amount of 
outwash, the first and third 
moraines being associated 
with the greatest masses. 
The material in the moraines 
Represents only a part of 
that removed to form the 
Successive steps in the valley 
profile. The lowermost one 
has an enormous volume, 
since it is the oldest and 
was built at a time when the valley was full of Avaste. It is fronted 
by a deep fill, over the dissected edge of which one may descend 
800 feet in half an hour. It is chiefly alluvial in character, whereas 
the next higher one is composed chiefly of bowlders and is fronted 
by a pronounced bowlder train, which includes a remarkable 
perched bowlder of huge size. Once the valley became cleaned 
out the ice Avould derive its material chiefly by the slower 
process of plucking and abrasion, hence would build much smaller 
moraines during later recessional stages, even though the stages 
were of equivalent length. 

There is a marked difference in the degree of dissection of the 




FiQ. 136 — Glacial sculpture on the south- 
western flank of the Cordillera Vileapampa. 
Flat-floored valleys and looped terminal mo- 
raines below and glacial steps and hanging 
valleys are characteristic. The present snow- 
flelds and glaciers are shown by dotted contours. 



208 THE ANDES OF SOUTHERN PERU 

moraines. The lowermost and oldest is so thoroughly dissected 
as to exhibit but little of its original surface. The second has 
been greatly modified, but still possesses a ridge-like quality and 
marks the beginning of a noteworthy flattening of the valley 
gradient. The third is as sharp-crested as a roof, and yet was 
built so long ago that the flat valley floor behind it has been modi- 
fied by the meandering stream. From this point the glacier re- 
treated up-valley several miles (estimated) without leaving more 
than the thinnest veneer on the valley floor. The retreat must, 
therefore, have been rapid and without even temporary halts until 
the glacier reached a position near that occupied today. Both the 
present ice tongnies and snowfields and those of a past age are 
emphasized by the presence of a patch of scrub and woodland that 
extends on the north side of the valley from near the snowline 
down over the glacial forms to the lower valley levels. 

The retreatal stages sketched above would call for no special 
comment if they were encountered in mountains in northern lati- 
tudes. They would be recognized at once as evidence of successive 
periodic retreats of the ice, due to successive changes in tempera- 
ture. To understand their importance when encountered in very 
low latitudes it is necessary to turn aside for a moment and con- 
sider two rival hypotheses of glacial retreat. First we have the 
hypothesis of periodic retreat, so generally applied to terminal 
moraines and associated outwash in glaciated mountain valleys. 
This implies also an advance of the ice from a higher position, 
the whole taking place as a result of a climatic change from 
warmer to colder and back again to warmer. 

But evidences of more extensive mountain glaciation in the 
past do not in themselves prove a change in climate over the whole 
earth. In an epoch of fixed climate a glacier system may so deeply 
and thoroughly erode a mountain mass, that the former glaciers 
may either diminish in size or disappear altogether. As the work 
of excavation proceeds, the catchment basins are sunk to, and at 
last below, the snowline; broad tributary spurs whose snows 
nourish the glaciers, may be reduced to narrow or skeleton ridges 
with little snow to contribute to the valleys on either hand; the 




Fig. 137. 




Pig. 138. 



Fig. 137 — Looking up a spurless flat-floored glacial trougli near the Chucuito pass 
in the Cordillera Vilcapampa from 14,200 feet (4,330 m.). Note the looped terminal 
and lateral moraines on the steep valley wall on the left. A stone fence from wall to 
wall serves to inclose the flock of the mountain shepherd. 

Fig. 138 — Tei-minal moraine in the glaciated Choquetira Valley below Choquetira. 
The people who live here have an abundance of stones for building corrals and stone 
houses. The upper edge of the timber belt (cold timber line) is visible beyond the 
houses. Elevation 12,100 feet (3,690 m.). 



EASTERN ANDES: CORDILLERA VILCAPAMPA 209 

glaciers retreat and at last disappear. There would be evidences 
of glaciation all a,bout the ruins of the former loftier mountain, 
but there would be no living glaciers. And yet the climate might 
remain the same throughout. 

It is this "topographic" hypothesis that Eeiss and Stiibel 
accept for the Ecuadorean volcanoes. Moreover, the volcanoes of 
Ecuador are practically on the equator — a very critical situation 
when we wish to use the facts they exhibit in the solution of such 
large problems as the contemporaneous glaciation of the two 
hemispheres, or the periodic advance and retreat of the ice over 
the whole earth. This is not the place to scrutinize either their 
facts or their hypothesis, but I am under obligations to state very 
emphatically that the glacial features of the Cordillera Vilca- 
pampa require the climatic and not the topographic hypothesis. 
Let us see why. 

The differences in degree of dissection and the flattening 
gradient up-valley that we noted in a preceding paragraph leave 
no doubt that each moraine of the bordering valleys in the Vilca- 
pampa region, represents a prolonged period of stability in the 
conditions of topography as well as of temperature and precipita- 
tion. If change in topographic conditions is invoked to explain 
retreat from one position to the other there is left no explanation 
of the periodicity of retreat which has just been established. If 
a period of cold is inaugurated and glaciers advance to an ulti- 
mate position, they can retreat only through change of climate 
effected either by general causes or by topographic development 
to the point where the snowfields become restricted in size. In 
the case of climatic change the ice changes are periodic. In the 
case of retreat due to topographic change there should be a steady 
or non-periodic falling back of the ice front as the catchment 
basins decrease in elevation and the snow-gathering ridges tribu- 
tary to them are reduced in height. 

Further, the matterhorns of the Cordillera Vilcapampa are not 
bare but snow-covered, vigorous glaciers several miles in length 
and large snowfields still survive and the divides are not aretes 
but broad ridges. In addition, the last two moraines, composed 



210 



THE ANDES OF SOUTHERN PERU 



of very loose material, are well preserved. They indicate clearly 
that the time since their fonnation has witnessed no wholesale 
topographic change. If (1) no important topographic changes 
have taken place, and (2) a vigorous glacier lay for a long period 
back of a given moraine, and (3) suddenly retreated several 
miles and again became stable, we are left Avithout confidence 
in the application of the topographic hypothesis to the glacial 

features of the Vilcapampa 
region. Glacial retreat may 
be suddenly begun in the 
case of a late stage of topo- 
graphic development, but it 
should be an orderly retreat 
marked by a large number 
of small moraines, or at 
least a plentiful strewing of 
the valley floor with debris. 
The number of moraines 
in the various glaciated val- 
leys of the Cordillera Vil- 
capampa differ, owing to 
differences in elevation and 
to the variable size of the 
catchment basins. All val- 
leys, however, display the 
same sudden change from moraine to moraine and the same 
characteristics of gradient. In all of them the lowermost 
moraine is always more deeply eroded than the higher 
moraines, in all of them glacial erosion was sufficiently pro- 
longed greatly to modify the valley walls, scour out lake basins, 
or broad flat valley floors, develop cirques, aretes, and pinnacled 
ridges in limited number. In some, glaciation was carried to the 
point where only skeleton divides remained, in most places broad 
massive ridges or mountain knots persist. In spite of all these 
differences successive moraines were formed, separated by long 
stretches either thinly covered with till or exposing bare rock. 




Fig. 139 — Glacial features on the eastern 
slopes of the Cordillera Vilcapampa. 



EASTERN ANDES: CORDILLERA VILCAPAMPA 211 

In examining this group of features it is important to rec- 
ognize the essential fact that though the number of moraines 
varies from valley to valley, the differences in character between 
the moraines at low and at high elevations in a single valley are 
constant. It is also clear that everywhere the ice retreated and 
advanced periodically, no matter Avith what topographic features 
it was associated, whether those of maturity or of youth in the 
glacial cycle. We, therefore, conclude that topographic changes 
had no significant part to play in the glacial variations in the 
Cordillera Vilcapampa. 

The country west of the Cordillera Vilcapampa had been re- 
duced to early topographic maturity before the Ice Age, and then 
uplifted with only moderate erosion of the masses of the inter- 
fluves. That on the east had passed through the same sequence 
of events, but erosion had been carried much farther. The reason 
for this is found in a strong climatic contrast. The eastern is 
the windward aspect and receives much more rain than the west- 
ern. Therefore, it has more streams and more rapid dissection. 
The result was that the eastern slopes were cut to pieces rapidly 
after the last great regional uplift ; the broad interfluves were nar- 
rowed to ridges. The region eastward from the crest of the 
Cordillera to the Pongo de Mainique looks very much like the 
western half of the Cascade Mountains in Oregon — the summit 
tracts of moderate declivity are almost all consumed. 

The effect of these climatic and topographic contrasts is mani- 
fested in strong contrasts in the position and character of the gla- 
cial forms on the opposite slopes of the range. At Pampaconas 
on the east the lowermost terminal moraine is at least a thousand 
feet below timber line. Between Vilcabamba pueblo and Puquiura 
the terminal moraine lies at 11,200 feet (3,414 m.). By contrast 
the largest Pleistocene glacier on the western slope, nearly twelve 
miles long, and the largest along the traverse, ended several miles 
below Choquetira at 11,500 feet (3,504 m.) elevation, or just at the 
timber line. Thus, the steeper descents of the eastern side of the 
range appear to have carried short glaciers to levels far lower 
than those attained by the glaciers of the western slope. 



212 



THE ANDES OF SOUTHERN PERU 



_~of Mili 



Scale^oX MU's;^'///;;, 



It seems at first strange that the largest glaciers were west 
of the divide between the Urubamba and the Apurimac, that is, on 
the relatively dry side of the range. The reason lies in a strik- 
ing combination of topo- 
graphic and climatic condi- 
tions. Snow is a mobile 
form of precipitation that is 
shifted about by the wind 
like a sand dune in the 
desert. It is not required, 
like water, to begin a do^\Ti- 
hill movement as soon as it 
strikes the earth. Thus, it 
is a noteworthy fact that 




snow drifting across the 
divides may ultimately cause 
the largest snowfields to lie 
where the least snow ac- 
tually falls. This is illus- 
trated in the Bighorns of 
Wyoming and others of our 
western ranges. It is, how- 
ever, not the Avet snow near 
the snowline, but chiefly the 
dry snow of higher altitudes 
that is affected. What is 
now the dry or leeward side 
of the Cordillera appears in glacial times to have actually re- 
ceived more snow than the wet windward side. 

The topography conspired to increase this contrast. In place 
of many streams, direct descents, a dispersion of snow in many 
valleys, as on the east, the western slopes had indirect descents, 
gentler valley profiles, and that higher degree of concentration of 
drainage which naturally goes with topographic maturity. For 
example, there is nothing in the east to compare with the big spur- 
less valley near the pass above Arma. The side walls were so 



Fig. 140 — Glacial sculpture in the heart 
of the Cordillera Vilcapampa. In places the 
topography has so high a relief that the glaciers 
seem almost to overhang the valleys. See Figs. 
96 and 179 for photographs. 



EASTERN ANDES: CORDILLERA VILCAPAMPA 213 

extensively trimmed that the valley was turned into a trough. 
The floor was smoothed and deepened and all the tributary gla- 
ciers were either left high up on the bordering slopes or entered 
the main valley with very steep profiles ; their lateral and terminal 
moraines now hang in festoons on the steep side walls. Moreover, 
the range crest is trimmed from the west so that the serrate sky- 
line is a feature rarely seen from eastern viewpoints. This may 
not hold true for more than a small part of the Cordillera. It was 
probably emphasized here less by the contrasts already noted 
than by the geologic structure. The eastward-flowing glaciers 
descended over dip slopes on highly inclined sandstones, as at 
Pampaconas. Those flowing westward worked either in a jointed 
granite or on the outcropping edges of the sandstones, where the 
quarrying process known as glacial plucking permitted the devel- 
opment of excessively steep slopes. 

There are few glacial steps in the eastern valleys. The west- 
tern valleys have a marvelous display of this striking glacial fea- 
ture. The accompanying hachure maps show them so well that 
little description is needed. They are from 50 to 200 feet high. 
Each one has a lake at its foot into which the divided stream 
trickles over charming waterfalls. All of them are clearly asso- 
ciated with a change in the volume of the glacier that carved the 
valley. Wherever a tributary glacier entered, or the side slopes 
increased notably in area, a step was formed. By retreat some 
of them became divided, for the process once begun would push 
the step far up valley after the manner of an extinguishing water- 
fall. 

The retreat of the steps, the abrasion of the rock, and the sap- 
ping of the cirques at the valley heads excavated the upper val- 
leys so deeply that they are nearly all, as W. D. Johnson has put 
it, ' ' down at the heel. ' ' Thus, above Arma, one plunges suddenly 
from the smooth, grassy glades of the strongly glaciated valley 
head down over the outer slopes of the lowermost terminal 
moraine to the steep lower valley. Above the moraine are fine 
pastures, in the steep valley below are thickets and rocky defiles. 
There are long quiet reaches in the streams of the glaciated valley 



214 THE ANDES OF SOUTHERN PERU 

heads besides pretty lakes and marshes. Below, the stream is 
swift, almost torrential. Arma itself is built upon alluvial de- 
posits of glacial origin. A mile farther down the valley is con- 
stricted and steep-walled — really a canyon. 

Though the glaciers have retreated to the summit region, they 
are by no means nearing extinction. The clear blue ice of the 
glacier descending from Mt. Soiroccocha in the Arma Valley 
seems almost to hang over the precipitous valley border. In 
curious contrast to its suggestion of cold and storm is the patch 
of dark green woodland which extends right up to its border. An 
earthquake might easily cause the glacier to invade the woodland. 
Some of the glaciers between Choquetira and Arma rest on 
terminal moraines whose distal faces are from 200 to 300 feet 
high. The ice descending southeasterly from Panta Mt. is a good 
illustration. Earlier positions of the ice front are marked by 
equally large moraines. The one nearest that engaged by the liv- 
ing glacier confines a large lake that discharges through a gap in 
the moraine and over a waterfall to the marshy floor of the valley. 

Retreat has gone so far, however, that there are only a few 
large glacier systems. Most of the tributaries have withdra^^^l 
toward their snowfields. In place of the twenty distinct glaciers 
now lying between the pass and the terminal moraine below Cho- 
quetira, there was in glacial times one great glacier with twenty 
minor tributaries. The cirques now partly filled with damp snow 
must then have been overflowing with dry snow above and ice be- 
low. Some of the glaciers were over a thousand feet thick ; a few 
were nearly two thousand feet thick, and the cirques that fed 
them held snow and ice at least a half mile deep. Such a remark- 
ably complete set of glacial features only 700 miles from the 
equator is striking evidence of the moist climate on the windward 
eastern part of the great Andean Cordillera, of the universal 
change in climate in the glacial period, and of the powerful domi- 
nating effects of ice erosion in this region of unsurpassed Alpine 
relief. 



EASTERN ANDES: CORDILLERA VILCAPAMPA 



215 



THE VILCAPAMPA BATHOLITH AND ITS TOPOGKAPHIC EFFECTS 

The main axis of the Cordillera Vilcapampa consists of granite 
in the form of a batholith between crystalline schists on the one 
hand (southwest), and Carboniferous limestones and sandstones 
and Silurian shales and slates on the other (northeast) . It is not 
a domal uplift in the region in which it was observed in 1911, but 





:^^^0, 


CORDILLERA VILCAPAMPA 


PAMPACONAS 
_,.---_'VALLEY 


--;;;;;^<^^ GRANITE 

^^^;;;;;^^::;^?''^ p R p H r R Y 


'^^^S^^^-^^ 


SAM DS TONE - — '^ 


WbwE. — — ■ — " TZ^ — 





Fig. 141 — Composite geologic section on the northeastern border of the Cordillera 
Vilcapampa, in the vicinitj' of Panipaconas, to show the deformative efifects of the 
granite intrusion. There is a limited amount of limestone near the border of the 
Cordillera. Both limestone and sandstone are Carboniferous. See Append!.^ B. See 
also Figs. 142 and 146. The section is about 15 miles long. 



an axial intrusion, in places restricted to a narrow belt not more 
than a score of miles across. As we should expect from the 
variable nature of the invaded material, the granite belt is not 
uniform in width nor in the character of its marginal features. 
In places the intrusion has produced strikingly little alteration 
of the country rock; in other localities the granite has been 
injected into the original material in so intimate a manner as 
almost completely to alter it, and to give rise to a very broad 
zone of highly metamorphosed rock. Furthermore, branches were 
developed so that here and there tributary belts of granite 
extend from the main mass to a distance of many miles. Out- 
lying batholiths occur whose common petrographic character and 
similar manner of occurrence leave little doubt that they are 
related abyssally to a common plutonic mass. 

The Vilcapampa batholith has two highly contrasted borders, 
whether we consider the degree of metamorphism of the country 
rock, the definition of the border, or the resulting topographic 
forms. On the northeastern ridge at Colpani the contact is so 
sharp that the outstretched arms in some places embrace typical 



216 



THE ANDES OF SOUTHERN PERU 



EASTERN BORDER RANGES 




Fig. 142 — The deformative efifeets oJ 
the Vilcapampa intrusion on the north- 
eastern border of the Cordillera. The 
deformed strata are heavy-bedded sand- 
stones and shales and the igneous rocks 
are chiefij' granites with bordering porphy- 
ries. Looking northwest near Puquiura. 
For conditions near Pampaconas, looking 
in the opposite direction, see Fig. 141. For 
conditions on the other side of the Cordil- 
lera see Fig. 146. 



granite on the one hand and almost unaltered shales and slates on 
the other. Inclusions or xenoliths of shale are common, however, 
ten and fifteen miles distant, though they are prominent features 
in a belt only a few miles wide. The lack of more intense contact 
effects is a little remarkable in view of the altered character of 

the inclusions, all of which are 
crystalline in contrast to the fis- 
sile shales from which they are 
chiefly derived. Inclusions with- 
in a few inches of the border 
fall into a separate class, since 
they show in general but trifling 
alteration and preserve their 
original cleavage planes. It ap- 
pears that the depth of the in- 
trusion must have been rela- 
tively slight or the intrusion sudden, or both shallow and sudden, 
conditions which produce a narrow zone of metamorphosed ma- 
terial and a sharp contact. 

The relation between shale and granite at Colpani is sho^vn 
in Fig. 143. Projections of granite extend several feet into the 

shale and slate and generally 

end in blunt barbs or knobs. 
In a few places there is an in- 
timate mixture of irregular 
slivers and blocks of crystal- 
lized sediments in a granitic 
groundmass, with sharp lines 
of demarcation between igneous 
and included material. The 
contact is vertical for at least 
several miles. It is probable 
that other localities on the con- 
tact exhibit much greater modification and invasion of the weak 
shales and slates, but at Colpani the phenomena are both simple 
and restricted in development. 




Fig. 143 — Relation of granite intru- 
sion to schist on the northeastern border 
of the Vilcapampa batholith near the 
bridge of Colpani, lower end of tlie granite 
Canyon of Torontoy. The sections are 
from 15 to 25 feet high and represent con- 
ditions at different levels along the well- 
defined contact. 



EASTERN ANDES: CORDILLERA VILCAPAMPA 217 

The highly mineralized character of the bordering sedimentary- 
strata, and the presence of numbers of complementary dikes, 
nearly identical in character to those in the parent granite now 
exposed by erosion over a broad belt roughly parallel to the con- 
tact, supplies a basis for the inference that the granite may under- 
lie the former at a slight depth, or may have had far greater meta- 
morphic effects upon its sedimentary roof than the intruded 
granite has had upon its sedimentary rim. 

The physiographic features of the contact belt are of special 
interest. No available physiographic interpretation of the topog- 
raphy of a batholith includes a discussion of those topographic 
and drainage features that are related to the lithologic character 
of the intruded rock, the manner of its intrusion, or the depth of 
erosion since intrusion. Yet each one of these factors has a dis- 
tinct topographic effect. We shall, therefore, turn aside for a 
moment from the detailed discussion of the Vilcapampa region 
to an examination of several physiographic principles and then 
return to the main theme for applications. 

It is recognized that igneous intrusions are of many varieties 
and that even batholithic invasions may take place in rather 
widely different ways. Highly heated magmas deeply buried be- 
neath the earth's surface produce maximum contact effects, those 
nearer the surface may force the strata apart without extreme 
lithologic alterations of the displaced beds, while through the 
stoping process a sedimentary cover may be largely absorbed and 
the magmas may even break forth at the surface as in ordinary 
vulcanism. If the sedimentary beds have great vertical variation 
in resistance, in attitude, and in composition, there may be af- 
forded an opportunity for the display of quite different effects 
at different levels along a given contact, so that a great variety 
of physical conditions will be passed by the descending levels of 
erosion. At one place erosion may have exposed only the summit 
of the batholith, at another the associated dikes and sheets and 
ramifying branches may be exposed as in the zone of fracture, at 
a third point the original zone of flowage may be reached with 
characteristic marginal schistosity, while at still greater depths 



218 THE ANDES OF SOUTHERN PERU 

there may be uncovered a highly metamorphosed rim of resistant 
sedimentary rock. 

The mere enumeration of these variable structural features is 
sufficient to show how variable we should expect the associated 
land forms to be. Were the forms of small extent, or had they 
but slight distinction upon comparison with other erosional ef- 
fects, they would be of little concern. They are, on the contrary, 
very extensively developed; they affect large numbers of lofty 
mountain ranges besides still larger areas of old land masses sub- 
jected to extensive and deep erosion, thus laying bare many batho- 
liths long concealed by a thick sedimentary roof. 

The differences between intruded and country rock dependent 
upon these diversified conditions of occurrence are increased or 
diminished according to the history of the region after batholithic 
invasion takes place. Eegional metamorphism may subsequently 
induce new structures or minimize the effects of the old. Joint 
systems may be developed, the planes widely spaced in one group 
of rocks giving rise to monolithic masses very resistant to the 
agents of weathering, while those of an adjacent group may be so 
closely spaced as greatly to hasten the rate of denudation. There 
may be developed so great a degree* of schistosity in one rock as 
to give rise (with vigorous erosion) to a serrate topography, on 
the other hand the forms developed on the rocks of a batholith 
may be massive and coarse-textured. 

To these diversifying conditions may be added many others 
involving a large part of the field of dynamic geology. It will 
perhaps suffice to mention two others : the stage of erosion and 
the special features related to climate. If a given intrusion has 
been accompanied by an important amount of uplift or marginal 
compression, vigorous erosion may follow, whereupon a chance 
will be offered for the development of the greatest contrast in the 
degree of boldness of topographic forms developed upon rocks of 
unequal resistance. Ultimately these contrasts will diminish in 
intensity, as in the case of all regional differences of relief, with 
progress toward the end of the normal cycle of erosion. If pene- 
planation ensue, only feeble topographic differences may mark 




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EASTERN ANDES: CORDILLERA VILCAPAMPA 219 

the line of contact which was once a prominent topographic fea- 
ture. With reference to the effects of climate it may be said sim- 
ply that a granite core of batholithic origin may extend above the 
snowline or above timber line or into the timbered belt, whereas 
the invaded rock may occur largely below these levels with obvi- 
ous differences in both the rate and the kind of erosion affecting 
the intruded mass. 

If we apply the foregoing considerations to the Cordillera 
Vilcapampa, we shall find some striking illustrations of the prin- 
ciples involved. The invasion of the granite was accompanied by 
moderate absorption of the displaced rock, and more especially 
by the marginal pushing aside of the sedimentary rim. The im- 
mediate effect must have been to give both intruded rock and coun- 
try rock greater height and marked ruggedness. There followed 
a period of regional compression and torsion, and the develop- 
ment of widespread joint systems with strikingly regular features. 
In the Silurian shales and slates these joints are closely spaced; 
in the granites they are in many places twenty to thirty feet 
apart. The shales, therefore, offer many more points of attack 
and have weathered down into a smooth-contoured topography 
boldly overlooked along the contact by walls and peaks of granite. 
In some cases a canyon wall a mile high is developed entirely on 
two or three joint planes inclined at an angle no greater than 15°. 
, The effect in the granite is to give a marked boldness of relief, 
nowhere more strikingly exhibited than at Huadquina, below 
Colpani, where the foot-hill slopes developed on shales and slates 
suddenly become moderate. The river flows from a steep and all 
but uninhabited canyon into a broad valley whose slopes are dot- 
ted with the terraced chacras, or farms, of the mountain Indians. 
The Torontoy granite is also homogeneous while the shales 
and slates together with their more arenaceous associates occur 
in alternating belts, a diversity which increases the points of at- 
tack and the complexity of the forms. Tending toward the same 
result is the greater hardness of the granite. The tendency of the 
granite to develop bold forms is accelerated in lofty valleys dis- 
posed about snow-clad peaks, where glaciers of great size once 



230 THE ANDES OF SOUTHERN PERU 

fexisted, and where small glaciers still linger. The plucking action 
of ice has an excellent chance for expression, since the granite 
may be quarried cleanly without the production of a large amount 
of spoil which would load the ice and diminish the intensity of its 
plucking action. 

As a whole the Central Andes passed through a cycle of ero- 
sion in late Tertiary time which was interrupted by uplift after 
the general surface had been reduced to a condition of topo- 
graphic maturity. Upon the granites mature slopes are not de- 
veloped except under special conditions (1) of elevation as in the 
small batholith above Chuquibambilla, and (2) where the granite 
is itself bordered by resistant schists which have upheld the sur- 
face over a broad transitional belt. Elsewhere the granite is 
marked by exceedingly rugged forms : deep steep-walled canyons, 
precipitous cirques, matterhorns, and bold and extended escarp- 
ments of erosion. In the shale belt the trails run from valley to 
valley in every direction without special difficulties, but in the 
granite they follow the rivers closely or cross the axis of the 
range by carefully selected routes which generally reach the limit 
of perpetual snow. Added interest attaches to these bold topo- 
graphic forms because of the ruins now found along the canyon 
walls, as at Torontoy, or high up on the summit of a precipitous 
spur, as at Machu Picchu near the bridge of San Miguel. 

The Vilcapampa batholith is bordered on the southwest by a 
series of ancient schists with which the granite sustains quite dif- 
ferent relations. No sharp dividing line is visible, the granite 
extending along the planes of foliation for such long distances as 
in places to appear almost interbedded with the schists. The re- 
lation is all the more striking in view of the trifling intrusions 
effected in the case of the seemingly much weaker shales on the 
opposite contact. Nor is the metamorphism of the invaded rock 
limited to simple intrusion. For several miles beyond the zone 
of intenser effects the schists have been enriched with quartz to 
such an extent that their original darker color has been changed 
to light gray or dull white. At a distance they may even appear 
as homogeneous and light-colored as the granite. At distant 



EASTERN ANDES: CORDILLERA VILCAPAMPA 221 

points the schists assume a darker hue and take on the characters 
of a rather typical mica schist. 

It is probable that the Vilcapampa intrusion is one of a family 
of batholiths which further study may show to extend over a 
much larger territory. The trail west of Abancay was followed 
quite closely and accidentally crosses two small batholiths of 
peculiar interest. Their limits were not closely followed out, but 




s 

Fig. 146 — Deformative eflfects on limestone strata of the granite intrusion on the 
southwestern border of the Vilcapampa batholith above Chuquibambilla. Fig. 147 is on 
the same border of the batholith several miles farther northwest. The granite mass 
on the right is a small outlier of the main batholith looking south. The limestone 
is Cretaceous. See Appendix C for locations. 

were accurately determined at a number of points and the remain- 
ing portion of the contact inferred from the topography. In the 
case of the larger area there may indeed be a connection west- 
ward with a larger mass which probably constitutes the ranges 
distant some five to ten miles from the line of traverse. 

These smaller intrusions are remarkable in that they appear 
to have been attended by little alteration of either invading or 
invaded rock, though the granites were observed to become dis- 
tinctly more acid in the contact zone. Space was made for them 
by displacing the sedimentary cover and by a marked shortening 
of the sedimentary rim through such structures as overthrust 
faults and folds. The contact is observable in a highly meta- 
morphosed belt about twenty feet wide, and for several hundred 
feet more the granite has absorbed the limestone in small amounts 
with the production of new minerals and the development of a dis- 
tinctly lighter color. The deformative effects of the batholithic 
invasion are shown in their gross details in Figs. 141, 142, and 146; 
the finer details of structure are represented in Fig. 147, which is 
drawn from a measured outcrop above Chuquibambilla. 

It will be seen that we have here more than a mere crinkling, 



222 



THE ANDES OF SOUTHERN PERU 



■*~^ 


5^ 


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K_ 






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-N 








^^^ 


S,^,^H^s 


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- 








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•'■^ 


^ COHSLOMERArt 








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~ UMESTOMt 








— 


LIMESrONE 

SH*Lt 

CONCLOMERAK 



Fig. 147 — Overthrust folds in detail on the 
southwestern border of the Vilcapampa batho- 
lith near Chuquibambilla. The section is fifteen 
feet high. Elevation, 13,100 feet (4,000 m.). 
For comparison with the structural effects of 
the Vilcapampa intrusion on the northeast see 
Fig. 142. 



such as the mica schists of the Cordillera Vilcapampa display. 
The diversified sedimentary series is folded and faulted on a large 
scale with broad structural undulations visible for miles along the 
abrupt valley walls. Here and there, however, the strata become 
weaker generally through the thinning of the beds and the more 
rapid alternation of hard and soft layers, and for short distances 

they have absoi'bed notable 
amounts of the stresses in- 
duced by the igneous intru- 
sions. In such places not 
only the structure but the 
composition of the rock 
shows the eifects of the in- 
trusion. Certain shales in 
the section are carbonaceous 
and in all observed cases the 
organic matter has been 
transformed to anthracite, a 
condition generally associated with a certain amount of minute 
mashing and a cementation of both limestone and sandstone. 

The granite becomes notably darker on approach to the north- 
eastern contact near Colpani; the proportion of ferro-magnesian 
minerals in some cases is so large as to give a distinctly black 
color in sharp contrast to the nearly white granite typical of the 
central portion of the mass. Large masses of shale foundered in 
the invading magma, and upon fusion gave rise to huge black 
masses impregnated with quartz and in places smeared or in- 
jected with granite magma. Everywhere the granite is marked 
by numbers of black masses which appear at first sight to be ag- 
gregations of dark minerals normal to the granite and due to dif- 
ferentiation processes at the time of crystallization. It is, how- 
ever, noteworthy that these increase rapidly in number on ap- 
proach to the contact, until in the last half-mile they appear to 
grade into the shale inclusions. It may, therefore, be doubted that 
they are aggregations. From their universal distribution, their 
uniform character, and their marked increase in numbers on ap- 



EASTERN ANDES: CORDILLERA VILCAPAMPA 223 

proach. to lateral contacts, it may reasonably be inferred that they 
represent foundered masses of country rock. Those distant from 
present contacts are in almost all cases from a few inches to a 
foot in diameter, while on approach to lateral contacts they are 
in places ten to twenty feet in width, as if the smaller areas rep- 
resented the last remnants of large inclusions engulfed in the 
magma near the upper or roof contact. They are so thoroughly 
injected with silica and also with typical granite magma as to 
make their reference to the country rock less secure on petro- 
graphical than on purely distributional grounds. 

A parallel line of evidence relates to the distribution of com- 
plementary dikes throughout the granite. In the main mass of 
the batholith the dikes are rather evenly distributed as to kind 
with a slight preponderance of the dark-colored group. Near the 
contact, however, aplitic dikes cease altogether and great num- 
bers of melanocratic dikes appear. It may be inferred that we 
have in this pronounced condition suggestions of strong influence 
upon the final processes of invasion and cooling of the granite 
magma, on the part of the country rock detached and absorbed 
by the invading mass. It might be supposed that the indicated 
change in the character of the complementary dikes could be 
ascribed to possible differentiation of the granite magma whereby 
a darker facies would be developed toward the Colpani contact. 
It has, however, been pointed out already that the darkening of 
the granite in this direction is intimately related to a marked in- 
crease in the number of inclusions, leaving little doubt that the 
thorough digestion of the smaller masses of detached shales is 
responsible for the marked increase in the number and variety 
of the ferro-magnesian and special contact minerals. 

Upon the southwestern border of the batholith the number of 
aplitic dikes greatly increases. They form prominent features, 
not only of the granite, but also of the schists, adding greatly to 
the strong contrast between the schist of the border zone and that 
outside the zone of metamorphism. In places in the border 
schists, these are so numerous that one may count up to twenty 
in a single view, and they range in size from a few inches to ten 



224. THE ANDES OF SOUTHERN PERU 

or fifteen feet. The greater fissility of the schists as contrasted 
with the shales on the opposite or eastern margin of the batholith 
caused them to be relatively much more passive in relation to the 
granite magma. They were not so much torn off and incorporated 
in the magma, as they were thoroughly injected and metamor- 
phosed. Added to this is the fact that they are petrographicallj^ 
more closely allied to the granite than are the shales upon the 
northeastern contact. 



CHAPTER XIV 
THE COASTAL TERRACES 

Along the entire coast of Peru are upraised and dissected ter- 
races of marine origin. They extend from sea level to 1,500 feet 
above it, and are best displayed north of Mollendo and in the des- 
ert south of Payta. The following discussion relates to that por- 
tion of the coast between Mollendo and Camana. 

At the time of the development of the coastal terraces the land 
was in a state of temporary equilibrium, for the terraces were 
cut to a mature stage as indicated by the following facts : (1) the 
terraces have great width — from one to five and more miles; (2) 
their inner border is straight, or, where curves exist, they are 
broad and regular; .(3) the terrace tops are planed off smoothly 
so that they now have an even gradient and an almost total ab- 
sence of rock stacks or unreduced spurs; (4) the mature slopes 
of the Coast Eange, strikingly uniform in gradient and stage of 
development (Fig. 148), are perfectly organized with respect to 
the inner edge of the terrace. They descend gradually to the ter- 
race margin, showing that they were graded with respect to sea 
level when the sea stood at the inner edge of the highest terrace. 

From the composition and even distribution of the thick-bed- 
ded Tertiary deposits of the desert east of the Coast Range, it is 
concluded that the precipitation of Tertiary time was greater than 
that of today (see p. 261). Therefore, if the present major streams 
reach the sea, it may also be concluded that those of an earlier 
period reached the sea, provided the topography indicates the per- 
fect adjustment of streams to structure. Lacustrine sediments 
are absent throughout the Tertiary section. Such through-flowing 
streams, discharging on a stable coast, would also have mature 
valleys as a consequence of long uninterrupted erosion at a fixed 
level. The Majes river must have cut through the Coast Range 

225 



226 THE ANDES OF SOUTHERN PERU 

at Camana then as now. Likewise the Vitor at Quilca must have 
cut straight across the Coast Range. An examination of the sur- 
face leading down from the Coast Range to the upper edge of 
these valleys fully confirms this deduction. Flowing and well- 
graded slopes descend to the brink of the inner valley in each 
case, where they give way to the gorge walls that continue the 
descent to the valley floor. 

Confirmatory evidence is found in the wide Majes Valley at 
Cantas and Aplao. (See the Aplao Quadrangle for details.) 
Though the observer is first impressed with the depth of the val- 
ley, its width is more impressive still. It is also clear that two 
periods of erosion are represented on its walls. Above Aplao the 
valley walls swing off to the west in a great embayment quite in- 
explicable on structural grounds; in fact the floor of the embay- 
ment is developed across the structure, which is here more dis- 
ordered than usual. The same is true below Cantas, as seen from 
the trail, which drops over two scarps to get to the valley floor. 
The upper, widely opened valley is correlated with the latter part 
of the period in which were formed the mature terraces of the 
coast and the mature slopes bordering the larger valleys where 
they cross the Coast Range. 

After its mature development the well-graded marine terrace 
was upraised and dissected. The deepest and broadest incisions 
in it were made where the largest streams crossed it. Shallower 
and narrower valleys were formed where the smaller streams that 
headed in the Coast Range flowed across it. Their depth and 
breadth was in general proportional to the height of that part of 
the Coast Range in which their headwaters lay and to the size of 
their catchment basins. 

When the dissection of the terrace had progressed to the point 
where about one-third of it had been destroyed, there came depres- 
sion and the deposition of Pliocene or early Pleistocene sands, 
gravels, and local clay beds. Everywhere the valleys were partly 
or wholly filled and over broad stretches, as in the vicinity of 
stream mouths and upon lower portions of the terrace, extensive 
deposits were laid down. The largest deposits lie several hours' 










Fia. 148. 




Fig. 149. 



Fig. 148 — The Coast Range between Mollendo and Arequipa at the end of June, 
1911. There is practically no grass and only a few dry shrubs. The fine network over 
the hill slopes is composed of interlacing cattle tracks. The cattle roam over these 
hills after the rains which come at long intervals. (See page 141 for description of 
the rains and the transformations they effect. For example, in October, 1911, these hills 
were covered with grass. ) 

Fig. 149 — The great marine terrace at Mollendo. See Fig. 150 for profile. 



THE COASTAL TERRACES 



22T 



ride south of Camana, where locally they 
attain a thickness of several hundred feet. 
Their upper surface was well graded and 
they show a prolonged period of deposi- 
tion in which the former coastal terrace 
was all but concealed. 

The uplift of the coast terrace and its 
subsequent dissection bring the physical 
history down to the present. The uplift 
was not uniform ; three notches in the ter- 
race show more faintly upon the granite- 
gneiss where the buried rock terrace has 
been swept clean again, more strongly 
upon the softer superimposed sands. They 
lie below the 700-foot contour and are in- 
significant in appearance beside the slopes 
of the Coast Range or the ragged bluff of 
the present coast. 

The eifect of the last uplift of the coast 
was to impel the Majes Eiver again to cut 
down its lower course nearly to sea level. 
The Pliocene terrace deposits are here en- 
tirely removed over an area several 
leagues wide. In their place an extensive 
delta and alluvial fan have been formed. 
At first the river undoubtedly cut down to 
base level at its mouth and deposited the 
cut material on the sea fioor, now shoal, 
for a considerable distance from shore. 
We should still find the river in that posi- 
tion had other agents not intervened. But 
in the Pleistocene a great quantity of 
waste was swept into the Majes Valley, 
whereupon aggradation began; and in the 
middle and lower valley it has continued 
down to the present. 



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228 THE ANDES OF SOUTHERN PERU 



Figs. 151-154 — These four diagrams represent the physical history and the corre- 
sponding physiographic development of the coastal region of Peru between Camanfi and 
Mollendo. The sedimentary beds in the bacicground of the first diagram are liypo- 
thetical and are supposed to correspond to the quartzites of the Majes Valley at Aplao. 



THE COASTAL TERRACES 229 

The effect has been not only the general aggradation of the 
valley floor, but also the development of a combined delta and 
superimposed alluvial fan at the valley mouth. The seaward ex- 
tension of the delta has been hastened by the gradation of the 
shore between the bounding headlands, thus giving rise to marine 
marshes in which every particle of contributed waste is firmly 
held. The plain of Camana, therefore, includes parts of each of 
the following: a delta, a superposed alluvial fan, a salt-water 
marsh, a fresh-water marsh, a series of beaches, small amounts 
of piedmont fringe at the foot of Pliocene deposits once trimmed 
by the river and by waves, and extensive tracts of indefinite fill. 
(See the Camana Quadrangle for details.) 

With the coastal conditions now before us it will be possible 
to attempt a correlation between the erosion features and the de- 
posits of the coast and those of the interior. An understanding 
of the comparisons will be facilitated by the use of diagrams. 
Figs. 151-154, and by a series of concise summary statements. 
From the relations of the figure it appears that : 

1. The Tertiary deposits bordering the Majes Valley east of 
the Coast Eange were in process of deposition when the sea 
planed the coastal terrace (Fig. 151). 

2. A broad mature marine terrace without stacks or sharply 
alternating spurs and reentrants (though the rock is a very re- 
sistant granite) is correlated with the mature grades of the Coast 
Range, with which they are integrated and with the mature pro- 
files of the main Cordillera. 

3. Such a high degree of topographic organization requires 
the dissection in the late stages of the erosion cycle of at least 
the inner or eastern border of the piedmont deposits of the des- 
ert, largely accumulated during the early stages of the cycle. 

4. Since the graded slopes of the Coast Eange on the one side 
descend to a former shore whose elevation is now but 1,500 feet 
above sea level, and since only ten to twenty miles inland on the 
other side of the range, the same kind of slope extends beneath 
Tertiary deposits 4,000 feet above sea level, it appears that ag- 
gradation of the outer (or western) part of the Tertiary deposits 



230 THE ANDES OF SOUTHERN PERU 

on the eastern border of the Coast Range continued down to the 
end of the cycle of erosion, though 

5. There must have been an outlet to the sea, since, as we 
have already seen, the water supply of the Tertiary was greater 
than that of today and the present streams reach the sea. More- 
over, the mature upper slopes and the steep lower slopes of the 
large valleys make a pronounced topographic unconformity, show- 
ing tw^o cycles of valley development. 

6. Upon uplift of the coast and dissection of the marine ter- 
races at the foot of the Coast Eange, the streams cut deep trenches 
on the floors of their former valleys (Fig. 152) and removed (a) 
large portions of the coast terrace, and (b) large portions of the 
Tertiary deposits east of the Coast Eange. 

7. Depression of the coastal terrace and its partial burial 
meant the drowning of the lower Majes Valley and its partial fill- 
ing with marine and later with terrestrial deposits. It also 
brought about the partial filling by stream aggradation of the 
middle portion of the valley, causing the valley fill to abut sharply 
against the steep valley walls. (See Fig. 155.) 

8. Uplift and dissection of both the terrace and its overlying 
sediments would be accompanied by dissection of the former val- 
ley fill, provided that the waste supply was not increased and that 
the uplift was regional and approximately equal throughout — 
not a bowing up of the coast on the one hand, or an excessive bow- 
ing up of the mountains on the other. But the waste supply has 
not remained constant, and the uplift has been greater in the 
Cordillera than on the coast. Let us proceed to the proof of these 
two conclusions, since upon them depends the interpretation of the 
later physical history of the coastal valleys. 

It is known that the Pleistocene was a time of augmented 
waste delivery. At the head of the broadly opened Majes Valley 
there was deposited a huge mass of extremely coarse waste sev- 
eral hundred feet deep and several miles long. Forward from it, 
interstratified with its outer margin, and continuing the same al- 
luvial grade, is a still greater mass of finer material which de- 
scends to lower levels. The fine material is deposited on the floor 




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THE COASTAL TERRACES 231 

of a valley cut into Tertiary strata, lience it is younger than the 
Tertiary. It is now, and has been for some time past, in process 
of dissection, hence it was not formed under present conditions of 
climate and relief. It is confidently assigned to the Pleistocene, 
since this is definitely known to have been a time of greater pre- 
cipitation and waste removal on the mountains, and deposition on 
the plains and the floors of mountain valleys. Such a conclusion 
appears, even on general grounds, to be but a shade less reliable 
than if we were able to find in the upper Majes Valley, as in so 
many other Andean valleys, similar alluvial deposits interlocked 
with glacial moraines and valley trains. 

In regard to the second consideration — the upbowing of the 
Cordillera — it may be noted that the valley and slope profiles of 
the main Cordillera shown on p. 191, when extended toward the 
margin of the mountain belt, lie nearly a mile above the level of 
the sea on the west and the Amazon plains on the east. The evi- 
dence of regional bowing thus afforded is checked by the depths of 
the mountain valleys and the stream profiles in them. The 
streams are now sunk from one to three thousand feet below their 
former level. Even in the case of three thousand feet of erosion 
the stream profiles are still ungraded, the streams themselves are 
almost torrential, and from one thousand to three thousand feet 
of vertical cutting must still be accomplished before the profiles 
will be as gentle and regular as those of the preceding cycle of 
erosion, in which were formed the mature slopes now lying high 
above the valley fioors. 

Further evidence of bowing is afforded by the attitude of the 
Tertiary strata themselves, more highly inclined in the case of 
the older Tertiary, less highly inclined in the case of the younger 
Tertiary. It is noteworthy that the gradient of the present val- 
ley floor is distinctly less than that of the least highly inclined 
strata. This is true even where aggradation is now just able to 
continue, as near the nodal point of the valley, above Aplao, 
where cutting ceases and aggradation begins. (See the Aplao 
Quadrangle for change of function on the part of the stream 
a half mile above Cosos). Such a progressive steepening of 



232 THE ANDES OF SOUTHERN PERU 

gradients in the direction of the oldest deposits, shows very 
clearly a corresponding progression in the growth of the Andes 
at intervals throughout the Tertiary. 

Thus we have aggradation in the Tertiary at the foot of the 
growing Andes ; aggradation in the Pliocene or early Pleistocene 
on the floor of a deep valley cut in earlier deposits ; aggradation 
in the glacial epoch; and aggradation now in progress. Basin 
deposits within the borders of the Peruvian Andes are relatively 
rare. The profound erosion implied by the development, first of 
a mature topography across this great Cordillera, and second of 
many deep canyons, calls for deposition on an equally great scale 
on the mountain borders. The deposits of the western border are 
a mile thick, but they are confined to a narrow zone between the 
Coast Range and the Cordillera. Whatever material is swept be- 
yond the immediate coast is deposited in deep ocean water, for 
the bottom falls off rapidly. The deposits of the eastern border 
of the Andes are carried far out over the Amazon lowland. Those 
of earlier geologic periods were largely confined to the mountain 
border, where they are now upturned to form the front range of 
the Andes. The Tertiary deposits of the eastern border are less 
restricted, though they appear to have gathered chiefly in a belt 
from fifty to one hundred miles wide. 

The deposits of the western border were laid down by short 
streams rising on a divide only 100 to 200 miles from the Pacific. 
Furthermore, they drain the dry leeward slopes of the Andes. 
The deposits of the wet eastern border were made by far larger 
streams that carry the waste of nearly the whole Cordillera. 
Their shoaling effect upon the Amazon depression must have been 
a. large factor in its steady growth from an inland sea to a river 
lowland. 



CHAPTER XV 
PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 

GENERAL FEATURES 

In the preceding chapter we employed geologic facts in the 
determination of the age of the principal topographic forms. 
These facts require further discussion in connection with their 
closest physiographic allies if we wish to show how the topog- 
raphy of today originated. There are many topographic details 
that have a fundamental relation to structure; indeed, without a 
somewhat detailed knowledge of geology only the broader and 
more general features of the landscape can be interpreted. In this 
chapter we shaU therefore refer not to the scenic features as in a 
purely topographic description, but to the rock structure and the 
fossils. A complete and technical geologic discussion is not de- 
sirable, first, because it should be based upon much more detailed 
geologic field work, and second because after all our main pur- 
pose is not to discuss the geologic features per se, but the physio- 
graphic background which the geologic facts afford. I make this 
preliminary observation partly to indicate the point of view and 
partly to emphasize the necessity, in a broad, geographic study, 
for the reconstruction of the landscapes of the past. 

The two dominating ranges of the Peruvian Andes, called the 
Maritime Cordillera and the Cordillera Vilcapampa, are com- 
posed of igneous rock — the one volcanic lava, the other intrusive 
granite. The chief rock belts of the Andes of southern Peru are 
shown in Fig. 157. The Maritime Cordillera is bordered on the 
west by Tertiary strata that rest unconformably upon Palaeozoic 
quartzites. It is bordered on the east by Cretaceous limestones 
that grade downward into sandstones, shales, and basal conglom- 
erates. At some places the Cretaceous deposits rest upon old 
schists, at others upon Carboniferous limestones and related 

233 



234. THE ANDES OF SOUTHERN PERU 

strata, upon small granite intrusives and upon old and greatly 
altered volcanic rock. 

The Cordillera Vilcapampa has an axis of granitic rock which 
was thrust upward through schists that now border it on the west 
and slates that now border it on the east. The slate series forms 
a broad belt which terminates near the eastern border of the 
Andes, where the mountains break down abruptly to the river 
plains of the Amazon Basin. The immediate border on the east 
is formed of vertical Carboniferous limestones. The narrow foot- 
hill belt is composed of Tertiary sandstones that grade into loose 
sands and conglomerates. The inclined Tertiary strata were lev- 
eled by erosion and in part overlain by coarse and now dissected 
river gravels, probably of Pleistocene age. Well east of the main 
border are low ranges that have never been described. They 
could not be reached by the present expedition on account of lack 
of time. On the extreme western border of that portion of the 
Peruvian Andes herein described, there is a second distinct border 
chain, the Coast Range. It is composed of granite and once had 
considerable relief, but erosion has reduced its former bold forms 
to gentle slopes and graded profiles. 

The continued and extreme growth of the Andes in later geo- 
logic periods has greatly favored structural and physiographic 
studies. Successive uplifts have raised earlier deposits once 
buried on the mountain flanks and erosion has opened canyons on 
whose walls and floors are the clearly exposed records of the past. 
In addition there have been igneous intrusions of great extent 
that have thrust aside and upturned the invaded strata exposing 
still further the internal structures of the mountains. From sec- 
tions thus revealed it is possible to outline the chief events in the 
history of the Peruvian Andes, though the outline is still neces- 
sarily broad and general because based on rapid reconnaissance. 
However, it shows clearly that the landscape of the present repre- 
sents but a temporary stage in the evolution of a great mountain 
belt. At the dawn of geologic history there were chains of moun- 
tains where the Andes now stand. They were swept away and 
even their roots deeply submerged under invading seas. Re- 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 235 



Fig. 157 — Outline sketch showing the 
principal rock belts of Peru along the 
seventy-third meridian. They are: 1, 
Pleistocene and Recent gravels and sands, 
the former partly indurated and slightly 
deformed, vfith the degree of deformation 
increasing toward the mountain border 
( south ) . 2, Tertiary sandstones, inclined 
from 15° to 30° toward the north and 
unconformably overlain by Pleistocene 
gravels. 3, fossil-bearing Carboniferous 
limestones with vertical dip. ^, non-fos- 
siliferous slates, shales, and slaty schists 
(Silurian) with great variation in degree 
of induration and in type of structure. 
South of the parallel of 13° is a belt of 
Carboniferous limestones and sandstones 
bordering (5) the granite axis of the 
Cordillera Vilcapampa. For its structural 
relations to the Cordillera see Figs. 141 and 
142. 6, old and greatly disturbed volcanic 
agglomerates, tuffs and porphyries, and 
quartzitic schists and granite-gneiss. 7, 
principally Carboniferous limestones north 
of the axis of the Central Ranges and 
Cretaceous limestones south of it. Local 
granite batholiths in the axis of the Central 
Ranges. 8, quartzites and slates predomi- 
nating with thin limestones locally. South 
of S is a belt of shale, sandstone, and lime- 
stone with a basement quartzite appearing 
on the valley floors. 9, a portion of the 
great volcanic field of the Central Andes 
and characteristically developed in the 
Western or Maritime Cordillera, through- 
out northern Chile, western Bolivia, and 
Peru. At Cotahuasi (see also Fig. 20) 
Cretaceous limestones appear beneath the 
lavas. 10, Tertiary sandstones of the 
coastal desert with a basement of old vol- 
canles and quartzites appearing on the 
valley walls. The valley floor is aggraded 
with Pleistocene and Recent alluvium. 11, 
granite-gneiss of the Coast Range. 12, late 
Tertiary or Pleistocene sands and gravels 
deposited on broad coastal terraces. For 
rock structure and character see the other 
figures in this chapter. For a brief desig- 
nation of index fossils and related forms 
see Appendix B. For the names of the 
drainage lines and the locations of the 
principal towns see Figs. 20 and 204. 




236 THE ANDES OF SOUTHERN PERU 

peated uplifts of the earth's crust reformed the ancient chains or 
created new ones out of the rock waste derived from them. Each 
new set of forms, therefore, exhibits some features transmitted 
from the past. Indeed, the landscape of today is like the human 
race — inheriting much of its character from past generations. 
For this reason the philosophical study of topographic forms re- 
quires at least a broad knowledge of related geologic structures. 

SCHISTS AND SILURIAN SLATES^ 

The oldest series of rocks along the seventy-third meridian of 
Peru extends eastward from the Vilcapampa batholith nearly to 
the border of the Cordillera, Fig. 157. It consists of (1) a great 
mass of slates and shales with remarkable uniformity of composi- 
tion and structure over great areas, and (2) older schists and 
siliceous members in restricted belts. They are everywhere thor- 
oughly jointed; near the batholith they are also mineralized and 
altered from their original condition; in a few places they have 
been intruded with dikes and other form of igneous rock. 

The slates and shales underlie known Carboniferous strata on 
their eastern border and appear to be a physical continuation of 
the fossiliferous slates of Bolivia; hence they are provisionally 
referred to the Silurian, though they may possibly be Devonian. 
Certainly the known Devonian exceeds in extent the known 
Silurian in the Central Andes but its lithological character is 
generally quite unlike the character of the slates here referred to 
the Silurian. The schists are of great but unknown age. They 
are unconformably overlain by known Carboniferous at Puquiura 
in the Vilcapampa Valley (Fig. 158), and near Chuquibambilla on 
the opposite side of the Cordillera Vilcapampa. The deeply 
weathered fissile mica schists east of Pasaje (see Appendix C for 
all locations) are also unconformably overlain by conglomerate 
and sandstone of Carboniferous age. While the schists vary con- 
siderably in lithological appearance and also in structure, they are 
everywhere the lowest rocks in the series and may with confidence 

' For a list of the fossils that form the basis of the age determinations in this 
chapter see Appendix B. 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 237 

be referred to the early Palaeozoic, while some of them may date 
from the Proteriozoic. 

The Silurian beds are composed of shale, sandstone, shaly 
sandstone, limestone, and slate with some slaty schist, among 
which the shales are predominent and the limestones least impor- 
tant. Near their contact with the granite the slate series is com- 
posed of alternating beds of sandstone and shale arranged in 
beds from one to three feet thick. At Santa Ana they become 




Porphyry 



Fig. 158 — Geologic sketch map of the lower Urubamba Valley. A single traverse 
was made along the valley, hence the boundaries are not accurate in detail. They were 
sketched in along a few lateral traverses and also inferred from the topography. 
The country rock is schist and the granite intruded in it is an arm of the main 
granite mass that constitutes the axis of the Cordillera Vilcapampa. The structure 
and to some degree the extent of the sandstone on the left are represented in Figs. 
141 and 142. 



more fissile and slaty in character and in several places are quar- 
ried and used for roofing. At Rosalina they consist of almost 
uniform beds of shale so soft and so minutely and thoroughly 
jointed as to weather easily. Under prolonged erosion they have, 
therefore, given rise to a well-rounded and soft-featured land- 
scape. Farther down the Urubamba Valley they again take on 
the character of alternating beds of sandstone and shale from a 
few feet to fifteen and more feet thick. In places the metamor- 
phism of the series has been carried further — the shales have be- 
come slates and the sandstones have been altered to extremely re- 
sistant quartzites. The result is again clearly shown in the topog- 
raphy of the valley wall which becomes bold, inclosing the river 



238 THE ANDES OF SOUTHERN PERU 

in narrow "pongos" or canyons filled with huge bowlders and 
dangerous rapids. The hills become mountains, ledges appear, 
and even the heavy forest cover fails to smooth out the natural 
ruggedness of the landscape. 

It is only upon their eastern border that the Silurian series 
includes calcareous beds, and all of these lie within a few thou- 
sand yards of the contact with the Carboniferous limestones and 
shales. At first they are thin paper-like layers; nearer the top 
they are a few inches wide and finally attain a thickness of ten 
or twelve feet. The available limestone outcrops were rigor- 
ously examined for fossils but none were found, although they 
are lavishly distributed throughout the younger Carboniferous 
beds just above them. It is also remarkable that though the 
Silurian age of these beds is reasonably inferred they are not 
separated from the Carboniferous by an unconformity, at least we 
could find none in this locality. The later beds disconformably 
overlie the earlier beds, although the sharp differences in lithology 
and fossils make it easy to locate the line of separation. The 
limestone beds of the Silurian series are extremely compact and 
unfossiliferous. At least in this region those of Carboniferous 
age are friable and the fossils varied and abundant. The Silurian 
beds are everywhere strongly inclined and throughout the eastern 
half or third of their outcrop in the Urubamba Valley they are 
nearly vertical. 

In view of the enormous thickness of the repeated layers of 
shale and sandstone this series is of great interest. Added im- 
portance attaches to their occurrence in a long belt from the 
eastern edge of the Bolivian highlands northward through Peru 
and possibly farther. From the fact that their disturbance has 
been on broad lines over wide areas with extreme metamorphism, 
• they are to be separated from the older mica-schists and the 
crumpled chlorite schists of Puquiura and Pasaje. Further rea- 
sons for this distinction lie in their lithologic difference and, to 
a more important degree, in the strong unconformity between the 
Carboniferous and the schists in contrast to the disconformable 
relations shown between the Carboniferous and Silurian fifty 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 239 

miles away at Pongo de Mainique. The naasbing and cmmpling 
that the schists have experienced at Puqniura is so intense, that 
were they a part of the Silurian series the latter should exhibit 
at least a slight unconformity in relation to the Carboniferous 
limestones deposited upon them. 

If our interpretation of the relation of the schists to the slates 
and shales be correct, we should have a mountain-making period 
introduced in pre-Silurian time, affecting the accumulated sedi- 
ments and bringing about their metamorphism and crumpling on 
a large scale. From the mountains and uplands thus created on 
the schists, sediments were washed into adjacent waters and ac- 
cumulated as even-bedded and extensive sheets of sands and muds 
(the present slates, shales, quartzites, etc.). Nowhere do the sedi- 
ments of the slate series show a conglomeratic phase; they are 
remarkably well-sorted and consist of material disposed with 
great regularity. Though they are coarsest at the bottom the 
lower beds do not show cross-bedding, ripple marking, or other 
signs of shallow-water conditions. Toward the upper part of the 
series these features, especially the ripple-marking, make their 
appearance. During the deposition of the last third of the series, 
and again just before the deposition of the limestone, the beds 
took on a predominantly arenaceous character associated with 
ripple marks and cross-bedding characteristic of shallow-water 
deposits. 

In the persistence of arenaceous sediments throughout the 
series and the distribution of the ripple marks through the upper 
third of the beds, we have a clear indication that the degree of 
shallowness was sufficient to bring the bottom on which the sedi- 
ments accumulated into the zone of current action and possibly 
wave action. It is also worth considering whether the currents 
involved were not of similar origin to those now a part of the 
great counter-clockwise movements in the southern seas. If so, 
their action would be peculiarly effective in the wide distribution 
of the sediment derived from a land mass on the eastern edge of 
a continental coast, since they would spread out the material to 
a greater and greater degree as they flowed into more southerly 



240 THE ANDES OF SOUTHERN PERU 

latitudes. Among geologic agents a broad ocean current of 
relatively uniform floAV would produce the most uniform effects 
throughout a geologic period, in which many thousand feet of 
clastic sediments were being accumulated. A powerful ocean cur- 
rent would also work on flats (in contrast to the gradient re- 
quired by near-shore processes), and at the same time be of such 
deeiD and steady flow as to result in neither ripple marks nor cross- 
bedding. 

The increasing volume of shallow-water sediments of uniform 
character near the end of the Silurian, indicates great crustal 
stability at a level which brought about neither a marked gain 
nor loss of material to the region. At any rate we have here no 
Devonian sediments, a characteristic shared by almost all the 
great sedimentary formations of Peru. At the beginning of the 
Carboniferous the water deepened, and great heaA'y-bedded lime- 
stones appear with only thin shale partings through a vertical dis- 
tance of several hundreds of feet. The enormous volume of 
Silurian sediments indicates the deep and prolonged erosion of 
the land masses then existing, a conclusion further supported (1) 
by the extensive development of the Silurian throughout Boli\aa 
as well as Peru, (2) by the entire absence of coarse material 
whether at the top or bottom of the section, and (3) by the very 
limited extent of older rock now exposed even after repeated and 
irregular uplift and deep dissection. Indeed, from the latter very 
striking fact, it may be reasonably argued that in a general way 
the relief of the country was reduced to sea level at the close of 
the Silurian. Over the perfected grades of that time there would 
then be afforded an opportunity for the effective transportation 
of waste to the extreme limits of the land. 

Further evidence of the great reduction of surface during the 
Silurian and Devonian is supplied by the extensive development 
of the Carboniferous strata. Their outcrops are now scattered 
across the higher portions of the Andean Cordillera and are pre- 
vailingly calcareous in their upper portions. Upon the eastern 
border of the Silurian they indicate marine conditions from the 
opening of the period, but at Pasaje in the Apurimac Valley they 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 241 

are marked by heavy beds of basal conglomerate and sandstone, 
and an abundance of ripple marking and other features associated 
with shallow-water and possibly near-shore conditions. 



CARBONIFEKOUS 

Carboniferous strata are distributed along the seventy-third 
meridian and rival in extent the volcanic material that forms the 
western border of the Andes. They range in character from 
basal conglomerates, sandstones, and shales of limited develop- 
ment, to enormous beds of extremely resistant blue limestone, in 
general well supplied with fossils. On the eastern border of the 

FRONT RANGE 




Fig. 159 — Topographic and structural section at the northeastern border of the 
Peruvian Andes. The slates are probably Silurian, the fo.ssiliferous limostonea are 
known Carboniferous, and the sandstones are Tertiary grading up to Pleistocene. 

Andes they are abruptly terminated by a great fault, the continua- 
tion northward of the marginal fault recognized in eastern 
Bolivia by Minchin ^ and farther north by the writer.'^ Coarse 
red sandstones with conglomeratic phase abut sharply and with 
moderate inclination against almost vertical sandstones and lime- 
stones of Carboniferous age. The break between the vertical lime- 
stones and the gently inclined sandstones is marked by a promi- 
nent scarp nearly four thousand feet high (Fig. 159), and the 
limestone itself forms a high ridge through which the Urubamba 
has cut a narrow gateway, the celebrated Pongo de Mainique. 

At Pasaje, on the western side of the Apurimac, the Carbonifer- 
ous again appears resting upon the old schists described on p. 236. 
It is steeply upturned, in places vertical, is highly conglomeratic, 
and in a belt a half-mile wide it forms true badlands topography. 

' Eastern Bolivia and the Gran Chaco, Proc. Royal Gcogr. Soc, Vol. 3, 1881, pp. 
401-420. 

•The Physiography of the Central Andes, Am. Journ. Sci., Vol. 28, 1909, p. 395. 



242 



THE ANDES OF SOUTHERN PERU 




It is succeeded by evenly bedded saudstones of fine and coarse 
composition in alternate beds, then follow shales and sandstones 
and finally the enormous beds of limestone that characterize the 
series. The structure is on the whole relatively simple in this 
region, the character and attitude of the beds indicating their ac- 
cumulation in a nearly horizontal position. Since the basal con- 
glomerate contains only pebbles and stones derived from the sub- 
jacent schists and does not contain granites like those in the Cor- 
dillera Vilcapampa batholith on the east it is concluded that the 

batholithic invasion was ac- 
companied by the compression 
and tilting of the Carbonifer- 
ous beds and that the batholith 
itself is post-Carboniferous. 
From the ridge summits above 
Huascatay and in the deep 
valleys thereabouts the Car- 
boniferous strata may be seen 
to extend far toward the west, 
and also to have great extent 
north and south. Because of 
their dissected, barej and, therefore, well-exposed condition they 
present exceptional opportunities for the study of Carboniferous 
geology in central Peru. 

Carboniferous strata again appear at Puquiura, Vilcapampa, 
and Pampaconas. They are sharply upturned against the Vilca- 
pampa batholith and associated volcanic material, chiefly basalt, 
porphyry, and various tuffs and related breccias. The Carbonifer- 
ous beds are here more arenaceous, consisting chiefly of alternat- 
ing beds of sandstone and shale. The lowermost beds, as at 
Pongo de Mainique, are dominantly marine, fossiliferous lime- 
stone beds having a thickness estimated to be over two miles. 

From Huascatay westAvard and southward the Carboniferous 
is in part displaced by secondary batholiths of granite, in part 
cut off or crowded aside by igneous intrusions of later date, and 
in still larger part buried under great masses of Tertiary volcanic 



Fig. 160 — The deformative effects of 
the granite intrusion of the Cordillera 
Vilcapampa are here shown as trans- 
mitted through ancient schists to the 
overlying conglomerates, sandstones, and 
limestones of Carboniferous age, in the 
Apurimac Valley at Pasaje. 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 243 




FiQ. 161 — Types of deformation north 
of Lambrama near Sotospampa. A 
dark basaltic rock has invaded both 
granite-gneiss and slate. Sills and dikes 
occur in great numbers. The topographic 
depression in the profile is the Lambrama 
Valley. See the Lambrama Quadrangle. 



material. Nevertheless, it remains the dominating rock type over 
the whole stretch of country from Hnascatay to Huancarama. In 
the northwestern part of the Abancay sheet its effect on the land- 
scape may be observed in the 
knife-like ridge extending from 
west to east just above Hu- 
ambo. Above Chuquibambilla 
it again outcrops, resting upon 
a thick resistant quartzite of 
unknown age. Fig. 162. It is 
strongly developed about 
Huadquirca and Antabamba 
and, still associated with a 
quartzite floor, it finally disap- 
pears under the lavas of the 

great volcanic field on the western border of the Andes. Figs. 141 
and 142 show its relation to the invading granite batholiths and 
Fig. 162 shows further structural features as developed about 
Antabamba where the great volcanic field of the Maritime Cordil- 
lera begins. 

Both the enormous thickness of the Carboniferous limestone 
series and the absence of clastic members over great areas in the 

upper portion of the series 
prove the widespread extent of 
the Carboniferous seas and their 
former occurrence in large in- 
terlimestone tracts from which 
they have since been eroded. 
At Puquiura they extend far 
over the schist, in fact almost 
completely conceal it ; at Pasaje 
they formerly covered the mica- 
schists extensively, their ero- 
sion in both cases being conditioned by the pronounced uplift and 
marginal deformation which accompanied the development of the 
Vilcapampa batholith. 




Fig. 162 — Sketch sections at Anta- 
bamba to show (a) deformed limestones 
on the upper edge of the geologic map, 
Fig. 163 A; and (b) the structural rela- 
tions of limestone and quartzite. See 
also Fig. 163. 



244 



THE ANDES OF SOUTHERN PERU 




Fig. 163 — Geologic sketch section to 
show the relation of the volcanic flows 
of Fig. 164 to the sandstones and quart- 
zites beneath. 



The degree of deformation of the Carboniferous sediments 
varies between simple uplift through moderate folding and com- 
plex disturbances resulting in nearly vertical attitudes. The sim- 
plest structures are represented at Pasaje, where the uplift of the 

intruded schists, marginal to 
the Vilcapampa batholith, has 
produced an enormous mono- 
clinal fold exposing the entire 
section from basal conglomer- 
ates and sandstones to the 
thickest limestone. Above Chu- 
quibambilla the limestones have 
been uplifted and very gently folded by the invasion of granite as- 
sociated with the main batholith and several satellitic batholiths of 
limited extent. A higher degree of complexity is shown at Pampa- 
conas (Fig. 141), where the main monoclinal fold is traversed al- 
most at right angles by secondary folds of great amplitude. The 
limestones are there carried to the limit of the winter snows almost 
at the summit of the Cordillera. The crest of each secondary anti- 
cline rises to form a group of conspicuous peaks and tabular 
ridges. Higher in the section, as at Puquiura, the sandstones are 
thrown into a series of huge anticlines and synclines, apparently 
by the marginal compression brought about at the time of the in- 
trusion of the granite core of the range. At Pongo de Mainique 
the whole of the visible Carboniferous is practically vertical, and 
is cut off by a great fault marking the abrupt eastern border of 
the Cordillera. 

It is noteworthy that the farther east the Carboniferous ex- 
tends the more dominantly marine it becomes, though marine beds 
of great thickness constitute a large part of the series in what- 
ever location. From Huascatay westward the limestones become 
more and more argillaceous, and finally give way altogether to an 
enormous thickness of shales, sandstones, and thin conglomerates. 
These were observed to extend with strong inclination westward 
out of the region studied and into and under the volcanoes crown- 
ing the western border of the Cordillera. Along the line of 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 245 



traverse opportunity was not afforded for further study of this 
aspect of the series, since our route led generally along the strike 
rather than along the dip of the heds. It is interesting to note, 
however, that these observations as to the increasing amounts of 
clastic material in a westward direction were afterwards con- 
firmed by Seiior Jose Bravo, the Director of the Bureau of Mines 
at Lima, who had found Carboniferous land plants in shales at 
Pacasmayo, the only fossils of 
their kind found in Peru. For- 
merly it had been supposed that 
non-marine Carboniferous was 
not represented in Peru. From 
the varied nature of the flora, 
the great thickness of the shales 
in which the specimens were col- 
lected, and the fact that the 
dominantly marine Carbonifer- 
ous elsewhere in Peru is of 
great extent, it is concluded that 
the land upon which the plants 
grew had a considerable area 
and probably extended far west 
of the present coast line. Since 
its emergence it has passed 
through several orogenic move- 
ments. These have resulted in 
the uplift of the marine portion 
of the Carboniferous, while the 
terrestrial deposits seem to have 
all but disappeared in the down-sunken blocks of the ocean floor, 
west of the great fault developed along the margin of the Cordil- 
lera. The following figures are graphic representations of this 
hypothesis. 

The wide distribution of the Carboniferous sediments and 
especially the limestones, together with the uniformity of the fos- 
sil faunas, makes it certain that the sea extended entirely across 




A 5 

Fig. 164 — Geologic sketch map and 
section, Antabamba region. The Anta- 
bamba River has cut through almost the 
entire series of bedded strata. 



246 



THE ANDES OF SOUTHERN PERU 




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PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 24-7 

tlie region now occupied by the Andes. However, from the rela- 
tion of the Carboniferous to the basal schists, and the most con- 
servative extension of the known Carboniferous, it may be in- 
ferred that the Carboniferous sea did not completely cover the 
entire area but was broken here and there by island masses in the 
form of an elongated archipelago. The presence of land plants 
in the Carboniferous of Pisco warrants the conclusion that a sec- 
ond island mass, possibly an island chain parallel to the tirst, ex- 
tended along and west of the present shore. 




EvS Alluvium ^^limestonelHIDSandstone 5 Shale ^Volcanic 



CEETACEOtJS 

The Cretaceous formations are of very limited extent in the 
belt of country under consideration, in spite of their generally 
wide distribution in Peru. They 
are exposed distinctly only on 
the western border of the Cor- 
dillera and in special relations. 
In the gorge of Cotahuasi, over 
seven thousand feet deep, about 
two thousand feet of Cretaceous 
limestones are exposed. The 
series includes only a very re- 
sistant blue limestone and ter- 
minates abruptly along a well- 
marked and highly irregnilar 
erosion surface covered by al- 
most a mile of volcanic ma- 
terial, chiefly lava flows. The 
character of the bottom of the 
section is likemse unknown, 
since it lies apparently far be- 
low the present level of ero- 
sion. 

The Cretaceous limestones of the Cotahuasi Canyon are every- 
where greatly and irregularly disturbed. Typical conditions are 
represented in the maps and sections. Figs. 166 and 167. They are 




Fig. 166 — Geologic sketch map and 
cross-section in the Cotahuasi Canyon at 
Cotahuasi. With a slight gap this figure 
continues Fig. 167 to the left. The sec- 
tion represents a spur of the irain plateau 
about 1,500 feet high in the center of tlie 
map. 



218 



THE ANDES OF SOUTHERN PERU 




Ir-./'.-l ftHuvlum II I HI Thick Congl.andSandstDne^^Limestone E8881 Volcanic . 




penetrated and tilted by igneous masses, apparently the feeders 
of the great lava sheets that form the western summit of the 
Cordillera. From the restricted development of the limestones 
along a western border zone it might be inferred that they rep- 
resent a very limited marine in- 
vasion. It is certainly clear that 
great deformative movements 
were in progress from at least 
late Palaeozoic time since all the 
Palaeozoic deposits are broken 
abruptly down in this direction, 
and, except for such isolated oc- 
currences as the land Carbonif- 
erous at Pacasmayo, are not 
found anywhere in the coastal 
region today. The Cretaceous 
is not only limited within a 
relatively narrow shore zone, 
but also, like the Palaeozoic, it 
is broken do^^^l toward the west, 
not reappearing from beneath 
the Tertiary cover of the desert 
region or upon the granite-gneisses that, form the foundation for 
all the known sedimentary strata of the inmiediate coast. 

From these considerations I think we have a strong suggestion 
of the geologic date assignable to the development of the great 
fault that is the most strongly marked structural and physio- 
graphic feature of the west coast of South America. Since the 
development of this fault is so intimately related to the origin of 
the Pacific Ocean basin its study is of special importance. The 
points of chief interest may be summarized as follows : 

(1) The character of the land Carboniferous implies a much 
greater extent of the land than is now visible. 

(2) The progressive coarsening of the Carboniferous deposits 
westward and their land derivation, together Avith the great thick- 
ness of the series, point to an elevated land mass in process of 



Fig. 167 — Geologic sketch map and 
cross-section in the Cotahuasi Canyon at 
Taurisma, above Cotahuasi. The relations 
of limestone and lava flows in the center 
of the map and on a spur top near the 
canyon floor. Thousands of feet of lava 
extend upward from the flows that cap 
the limestone. 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 249 

erosion west of the series as a whole, that is west of the present 
coast. 

(3) The restricted development of the Cretaceous seas upon 
the western border of the Carboniferous, and the still more re- 
stricted development of the Tertiary deposits between the moun- 
tains and the present coast, point to increasing definition of the 
submarine scarp through the Mesozoic and the Tertiary. 

(4) The Tertiary deposits are all clearly derived from the 
present mountains and have been washed seaward down slopes 
with geographic relations approximately like those of the present. 

(5) From the great width, deep dissection, and subsequent 




Clayg and sanda. 

Red sandstone and shale. 

Gray and yellow sandstone and shale. 

Basal sandstone. 
Volcanic agglomerate. 
Volcanic flows. 

Slaty schist. 
Granite. 

Fig. 168 — Composite structure section representing the succession of rocks in the 
Urubamba Valley from Urubamba to Torontoy. 

burial of the Tertiary terraces of the coast, it is clear that the 
greater part of the adjustment of the crust to which the bordering 
ocean basin is due was accomplished at least by mid-Tertiary 
time. 

Aside from the fossiliferous limestones of known Cretaceous 
age there have been referred to the Cretaceous certain red sand- 
stones and shales marked, especially in the central portions of the 
Cordillera, by the presence of large amounts of salt and gypsum. 
These beds were at first considered Permian, but Steinmann has 
since found at Potosi related and similar formations with Creta- 
ceous fossils. In this connection it is also necessary to add that 
the great red sandstone series forming the eastern border of the 
Andes in Bolivia is of uncertain age and has likewise been re- 



250 THE ANDES OF SOUTHERN PERU 

ferred to the Cretaceous, though the matter of its age has not yet 
been definitely determined. In 1913 I found it appearing in north- 
western Argentina in the Calchaqui Valley in a relation to the 
main Andean mass, similar to that displayed farther north. It 
contains fossils and its age was, therefore, readily determinable 
there.* 

In the Peruvian field the red beds of questionable age were not 
examined in sufficient detail to make possible a definite age de- 
termination. They occur in a great and only moderately disturbed 
series in the Anta basin north of Cuzco, but are there not fos- 
siliferous. The northeastern side of the hill back of Puqura (of 
the Anta basin: to be distinguished from Puquiura in the Vilca- 
bamba Valley) is composed largely of rocks of this class. In a 
few places their calcareous members have been weathered out in 
such a manner as to show karst topography. Where they occur 
on the well-drained brow of a bluff the caves are used in place 
of houses by Indian farmers. The large and strikingly beautiful 
Lake Huaipo, ten miles north of Anta, and several smaller, neigh- 
boring lakes, appear to have originated in solution depressions 
formed in these beds. 

The structural relation of the red sandstone series to the older 
rocks is well displayed about half-way between Urubamba and 
Ollantaytambo in the deep Urubamba Valley. The basal rocks are 
slaty schist and granite succeeded by agglomerates and basalt por- 
phyries upon whose eroded surfaces (Fig. 169) are gray to yel- 
low cross-bedded sandstones. Within a few hundred feet of the 
unconformity gypsum deposits begin to appear and increase in 
number to such an extent that the resulting soil is in places ren- 
dered worthless. Copper-stained bands are also common near the 
bottom of the series, but these are confined to the lower beds. 
Higher up in the section, for example, just above the gorge between 
Urubamba and Ollantaytambo, even-bedded sandstones occur 
whose most prominent characteristic is the regular succession of 

* See paper by H. S. Palmer, my assistant on the Expedition to the Central Andes, 
1913, entitled: Geological Notes on the Andes of Northwestern Argentina, Am. Journ. 
Sci., Vol. 38, 1914, pp. 309-330. 



»4 . 



%^ -_^ 



•^ .> 



:<L,s^^ 









^^^\>' 






:^i 




FlQ. 169. 




Fig. 170. 

Fig. 169 — The line of unconformity between the igneous basement rocks (agglom- 
erates at this point) and the quartzites and sandstones of the Urubamba Valley, 
between the town of Urubamba and Ollantaytambo. 

Fig. 170 — The inclined lower and horizontal upper sandstone on the southeastern 
wall of the Majes Valley at Hacienda Cantas. The section is a half-mile high. 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 251 

coarse and fine sandstone beds. Such alternations of character in 
sedimentary rocks are commonly marked by alternating shales 
and sandstones, but in this locality shales are practically absent. 
Toward the top of the section gypsum deposits again appear first 
as beds and later, as in the case of the hill-slope on the southern 
shore of Lake Huaipo, as veins and irregular masses of gypsum. 
The top of the deformed Cretaceous (!) is eroded and again cov- 
ered unconformably by practically flat-lying Tertiary deposits. 

TEETIAEY 

The Tertiary deposits of the region under discussion are 
limited to three regions: (1) the extreme eastern border of the 
main Cordillera, (2) intermontane basins, the largest and most 
important of which are (a) the Cuzco basin and (b) the Titicaca- 
Poopo basin on the Peruvian-Bolivian frontier, and (3) in the 
west-coast desert and in places upon the huge terraces that form 
a striking feature of the topography of the coast of Peru. 

It has already been pointed out that the eastern border of the 
Cordillera is marked by a fault of great but undetermined throw, 
whose topographic importance may be estimated from the fact 
that even after prolonged erosion it stands nearly four thousand 
feet high. Cross-bedded and ripple-marked features and small 
lenses of conglomerate are common. The beds now dip at an 
angle approximately 20° to 50° northward at the base of the scarp, 
but have decreasing dip as they extend farther north and east. 
It is noteworthy that the deposits become distinctly conglomeratic 
as flatter dips are attained, and that there seems to have been a 
steady accumulation of detrital material from the mountains for 
a long period, since the deposits pass in unbroken succession from 
the highly indurated and massive beds of the mountain base to 
loose conglomerates that now weather down much like an ordi- 
nary gravel bank. In a few places just below the mouth of the 
Ticumpinea, logs about six inches in diameter were observed 
embeded in the deposits, but these belong distinctly to the upper 
horizons. 

The border deposits, though they vary in dip from nearly flat 



252 THE ANDES OF SOUTHERN PERU 

to 50°, are everywhere somewhat incliued and now lie up to sev- 
eral hundred feet above the level of the Urubamba Eiver. Their 
upper surface is moderately dissected, the degree of dissection be- 
ing most pronounced where the dips are steepest and the height 
greatest. In fact, the attitude of the deposits and their progres- 
sive change in character point toward, if they do not actually 
prove, the steady and progressive character of the beds first de- 
posited and their erosion and redeposition in beds now higher in 
the series. 

Upon the eroded upper surfaces of the inclined border de- 
posits, gravel beds have been laid which, from evidence discussed 
in a later paragraph, are without doubt referable to the Pleis- 
tocene. These in turn are now dissected. They do not extend to 
the highest summits of the deformed beds but are confined, so 
far as observations have gone, to elevations about one hundred 
feet above the river. From the evidence that the overlying hori- 
zontal beds are Pleistocene, the thick, inclined beds are referred 
to Tertiary age, though they are nowhere fossiliferous. 

Observations along the Urubamba Kiver were extended as far 
northward as the mouth of the Timpia, one of the larger tribu- 
taries. Upon returning from this iioint by land a wide view of 
the country was gained from the four-thousand-foot ridge of 
vertical Carboniferous limestone, in which it appeared that low 

« 

and irregular strike ridges continue the features of the Tertiary 
displayed along the mountain front far northAvard as well as east- 
ward, to a point where the higher ridges and low mountains of 
older rock again appear — the last outliers of the Andean system 
in Peru. Unfortunately time enough was not available for an ex- 
tension of the trip to these localities whose geologic characters 
still remain entirely unknown. From the topographic aspects of 
the country, it is, however, reasonably certain that the whole in- 
tervening depression betAveen these outlying ranges and the 
border of the main Cordillera, is filled with inclined and now dis- 
sected and partly covered Tertiary strata. The elevation of the 
upper surface does not, however, remain the same; it appears to 
decrease steadily and the youngest Tertiary strata disappear 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 253 

from view below the sediments of either the Pleistocene or the 
present river gravels. In the more central parts of the depres- 
sion occupied by the Urubamba Valley, only knobs or ridges pro- 
ject here and there above the general level. 

The Coastal Tertiary 

The Tertiary deposits of the Peruvian desert region southwest 
of the Andes have many special features related to coastal de- 
formation, changes of climate, and great Andean uplifts. They 
lie between the west coast of Peru at Camana and the high, lava- 
covered country that forms the western border of the Andes and 
in places are over a mile thick. They are non-fossiliferous, cross- 
bedded, ripple-marked, and have abundant lenses of conglomerate 
of all sizes. The beds rest upon an irregular floor developed upon 
a varied mass of rocks. In some places the basement consists of 
old strata, strongly deformed and eroded. In other places it con- 
sists of a granite allied in character and probably in origin with 
the old granite-gneiss of the Coast Range toward the west. Else- 
where the rock is lava, evidently the earliest in the great series 
of volcanic flows that form this portion of the Andes. 

The deposits on the western border of the Andes are excel- 
lently exposed in the Majes Valley, one of the most famous in 
Peru, though its fame rests rather upon the excellence and abun- 
dance of its vineyards and wines than its splendid geologic sec- 
tions. Its head lies near the base of the snow-capped peaks of 
Coropuna ; its mouth is at Camana on the Pacific, a hundred miles 
north of MoUendo. It is both narrow and deep; one may ride 
across its floor anywhere in a half hour. In places it is a narrow 
canyon. Above Cantas it is sunk nearly a mile below the level of 
the desert upland through which it flows. Along its borders are 
exposed basal granites, old sedimentaries, and lavas ; inter-bedded 
with it are other lavas that lie near the base of the great volcanic 
series; through it still project the old granites of the Coast 
Range; and upon it have been accumulated additional volcanic 
rocks, wind-blown deposits, and, finally, coarse wash formed dur- 
ing the glacial period. From both the variety of the formations, 



254 THE ANDES OF SOUTHERN PERU 

the small amount of marginal dissection, and the excellent expo- 
sures made possible by the deep erosion and desert climate, the 
Majes Valley is one of the most profitable places in Peru for 
physiographic and geologic study. 

The most complete succession of strata (Tertiary) occurs just 
below Cantas on the trail to Jaguey (Fig. 171). Upon a floor of 
granite-gneiss, and alternating beds of quartzite and shale belong- 



COAST RANGE 


COASTAL DESERT 




HARITIKE COROILUaA 




^_--'=='=^ 


?^VA5 


^„^ UVAS 


,,<:=i;^^^=a=~,= 




*.V^''' 


WrIH GRJtNITC INTRUSIOnS 




\ VAIUY FLOOR »T TIME Of ah£*TtSt UPIIFT AND OlSatCTION 



Fig. 171 — Generalized sketch section to show the structural relations of the Mari- 
time Cordillera, the desert pampas, and the Coast Range. 

ing to an older series, are deposited heavy beds of red sandstone 
with many conglomerate lenses. The sandstone strata are meas- 
urably deformed and their upper surfaces moderately dissected. 
Upon them have been deposited unconformably a thicker series 
of deposits, conglomerates, sandstones, and finer mnd-blown ma- 
terial. The basal conglomerate is very coarse — much like beach 
material in both structure and composition, and similar to that 
along and south of the present coast at Camana. Higher in the 
section the material is prevailingly sandy and is deposited in 
regular beds from a few inches to a few feet in thickness. Near 
the top of the section are a few hundred feet of strata chiefly wind 
deposited. Unconformably overlying the Avhole series and in 
sharp contrast to the fine wind-blown stuff below it, is a third 
series of coarse deposits about five hundred feet thick. The top- 
most material, that forming the surface of the desert upland, con- 
sists of wind-blown sand now shifted by the wind and gathered 
into sand dunes or irregular drifts, banks of white earth, "tierra 
blanca, ' ' and a pebble pavement a few inches thick. 

If the main facts of the above section are now summarized 
they will facilitate an understanding of other sections about to be 
described, inasmuch as the summary will in a measure anticipate 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 255 



our conclusions concerning tlie origin of the deposits and their 
subsequent history. The sediments in the Majes Valley between 
Cantas and Jaguey consist of three series separated by two un- 
conformities. The lowermost series is evenly bedded and rather 
uniform in composition and topographic expression, standing 
forth in huge cliffs several hundred feet high on the eastern side 



COAST RftNOE 
LAS LDMflS 



LA (tmcONAOA MOQtIEGUA srERRA 

LAS PAMPAS JSSym. 



SEA LEVEL— 




STAUCTURE UNKNOWN 



Fig. 172 — Geologic relations of Coast Range, desert deposits, and Maritime 
Cordillera at Moquegua, Peru. After G. I. Adams; Bol. de Minas del Peru, Vol. 2, 
No. 4, 1906, p. 20. 

of the valley. This lower series 'is overlain by a second series, 
which consists of coarse conglomerate grading into sand and ulti- 
mately into very fine fluffy wind-deposited sands and silts. The 
lower series, is much more deformed than the upper, showing that 
the deforming movements of later geologic times have been much 
less intense than the earlier, as if there had been a fading out or 
weakening of the deforming agents. Finally there is a third 
series several hundred feet thick which forms the top of the 
section. 

Three other sections may now be examined, one immediately 
below Cantas, one just above, and one opposite Aplao. The sec- 
tion below Cantas is shown 
in Fig. 173, and indicates 
a lower series of red sand- 
stones crossed by vertical 
faults and unconformably 
overlain by nearly hori- 
zontal conglomerates, sandstones, etc., and the whole faulted again 
with an inclined fault having a throw of nearly 25°. A white to 
gray sandstone unconformably overlying the red sandstone is 
shown interpolated between the lowermost and uppermost series, 
the only example of its kind, however. No important differences 




Fig. 173 — Sketch section to show structural 
details on the walls of the Majes Valley near 
Aplao, looking south. 



256 THE ANDES OF SOUTHERN PERU 

in lithograpliical character may be noted between these and the 
beds of the preceding section. 

Again just above Cantas on the east side of the valley is a 
clean section exposing about two thousand feet of strata in a half 
mile of distance. The foundation rocks are old quartzites and 
shales in regularly alternating beds. Upon their uneven upper 
surfaces are several thousand feet of red sandstones and conglom- 
erates, which are both folded and faulted with the underlying 
quartzites. Above the red sandstones is a thick series of gray 
sandstones and silts which makes the top of the section and uncon- 
formably overlies the earlier series. 

A similar succession of strata was observed at Aplao, still 
farther up the Majes Valley, Fig. 174. A greatly deformed and 
metamorphosed older series is unconformably overlaid by a great 




Fig. 174 — -The structural relations of the strata on the border of the Majes Valley 
at Aplao, looking west. Field sketch from opposite side of valley. Height of section 
about 3,000 feet; length about ten miles. 

thickness of younger strata. The younger strata may be again 
divided into two series, a lower series consisting chiefly of red 
sandstones and an upper consisting of gray to yellow, and only 
locally red sands of finer texture and more uniform composition. 
The two are separated by an erosion surface and only the upper 
series is tilted regionally seaward with faint local deformation; 
the lower series is both folded and faulted Avith overthrusts ag- 
gregating several thousand feet of vertical and a half mile of 
horizontal displacement. 

The above sections all lie on the eastern side of the Majes Val- 
ley. From the upper edge of the valley extensive views were 
gained of the strata on the opposite side, and two sections, though 
they were not examined at close range, are at least worth com- 
paring with those already given. From the narrows below Can- 
tas the structure appears as in Figs. 175-176, and shows a deform- 
ing movement succeeded by erosion in a lower series. The upper 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 257 

series of sedimentary rock has suffered but slight deformation. 
A still more highly deformed basal series occurs on the right of 
the section, presumably the older quartzites. At Huancarqui, op- 
posite Aplao, an extensive view was gained of the western side 




Fie. 175 — Sketch section to show the structural details of the strata on the south 
wall of the Majes Valley near Cantas. The section is two miles long. 

of the valley, but the lower Tertiary seems not to be represented 
here, as the upper undeformed series rests unconformably upon 
a tilted series of quartzites and slates. Farther up the Cantas 
valley (an hour's ride above Aplao) the Tertiary rests upon vol- 
canic flows or older quartzites or the granite-gneiss exposed here 
and there along the valley floor. 

In no part of the sedimentaries in the Majes Valley were fos- 
sils found, save in the now uplifted and dissected sands that over- 
lie the upraised terraces along the coast immediately south of 




Fig. 176 — Composite geologic section to show the structural relations of the 
rocks on the western border of the Maritime Cordillera. The inclined strata at the 
right bottom represent older rocks; in places igneous, in other places sedimentary. 

Camana and also back of MoUendo. Like similar coastal deposits 
elsewhere along the Peruvian littoral, the terrace sands are of 
Pliocene or early Pleistocene age. The age of the deposits back 
of the Coast Eange is clearly greater than that of the coastal de- 
posits, (1) since they involve two unconformities, a mile or more 
of sediments, and now stand at least a thousand feet above the 
highest Pliocene (or Pleistocene) in the Camana Valley, and (2) 
because the erosion history of the interior sediments may be cor- 
related with the physiographic history of the coastal terraces and 
the correlation shows that uplift and dissection of the terraces 
and of the interior deposits went hand in hand, and that the de- 



258 THE ANDES OF SOUTHERN PERU 

posits on the terraces may similarly be correlated with alluvial 
deposits in the valley. 

We shall now see what further ground there is for the de- 
termination of the age of these sediments. Just below Chuqui- 
bamba, where they first appear, the sediments rest upon a floor of 
volcanic and older rock belonging to the great field now kno^\^l 
from evidence in many localities to have been formed in the early 
Tertiary, and here known to be post-Cretaceous from the rela- 
tions between Cretaceous limestones and volcanics in the Cota- 
huasi Valley (see p. 247). Although volcanic flows were noted 
interbedded with the desert deposits, these are few in number, in- 
significant in volume, and belong to the top of the volcanic series. 
The same may be said of the volcanic flows that locally overlie 
the desert deposits. We have then definite proof that the sand- 
stones, conglomerates, and related formations of the Majes Val- 
ley and bordering uplands are older than the Pliocene or early 
Pleistocene and younger than the Cretaceous and the older Ter- 
tiary lavas. Hence it can scarcely be doubted that thej^ represent 
a considerable part of the Tertiary period, especially in view of 
the long periods of accumulation which the thick sediments rep- 
resent, and the additional long periods represented by the two 
well-marked unconformities between the three principal groups of 
strata. 

If we now trace the physical history of the region we have 
first of all a deep depression between the granite range along the 
coast- and the western flank of the Andes. Here and there, as in 
the Vitor, the Majes, and other valleys, there were gaps through 
the Coast Eange. Nowhere did the relief of the coastal chain ex- 
ceed 5,000 feet. The depression had been partly filled in early 
geologic (probably early Paleozoic) time by sediments later de- 
formed and metamorphosed so that they are now quai'tzites and 
shales. The greater resistance of the granite of the Coast Eange 
resulted in superior relief, while the older deformed sedimentaries 
were deeply eroded, with the result that by the beginning of the 
Tertiary the basin quality of the depression was again empha- 
sized. All these facts are expressed graphically in Fig. 171. On 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 259 

the western flanlis of the granite range no corresponding sedi- 
mentary deposits are found in this latitude. The sea thus appears 
to have stood farther west of the Coast Range in Paleozoic times 
than at present. 

For the later history it is necessary to assemble the various 
Tertiary sections described on the preceding pages. First of all 
we recognize three quite distinct types of accumulations, for which 



Coarse alluvium alternating with fine wind- 
blown desert deposits. 
Upper sandstone series. 

Lower sandstone series. 

Quartzites. 




Volcanic flows. 

Granite-gneiss. 
Fig. 177 — Composite structure section at Aplao. 

we shall have to postulate three sets of conditions and possibly 
three separate agents. The first or lowermost consists of even- 
bedded deposits of red and gray sandstones, the former color pre- 
dominating. The material is in general well-sorted save locally, 
where Ifenses and even thin beds of conglomerate have been devel- 
oped. There is, however, about the whole series a uniformity and 
an orderliness in striking contrast to the coarse, cross-bedded, and 
irregular material above the unconformity. On their northeast- 
em or inner margin the sandstones are notably coarser and 
thicker, a natural result of proximity to the mountains, the source 
of the material. The general absence of wind-blown deposits is 
marked; these occur entirely along the eastern and northern por- 
tions of the deposits and are recognized (1) by their peculiar 
cross-bedding, and (2) by the fact that the cross-bedding is di- 
rected northeastward in a direction contrary to the regional dip 
of the series, a condition attributable to the strong sea breezes 
that prevail every afternoon in this latitude. 

The main body of the material is such as might be deposited 
on the Avide flood plains of piedmont streams during a period of 



260 THE ANDES OF SOUTHERN PERU 

prolonged erosion on surrounding liigblands lliat served as the 
feeding grounds of the streams. The alternations in the charac- 
ter of the deposits, alternations which, in a general view, give a 
banded appearance to the rock, are produced by successions of 
beds of fine and coarse material, though all of it is sandstone. 
Such successions are probably to be correlated with seasonal 
changes in the volume and load of the depositing streams. 

To gain an idea of the conditions of deposition we may take 
the character of the sediments as described above, and from them 
draw deductions as to the agents concerned and the manner of 
their action. 

We may also apply to the area the conclusions drawn from 
the study of similar deposits now in process of formation. AVe 
have between the coast ranges of northern Chile and the western 
flanks of the Cordillera Sillilica, probably the best example of 
piedmont accumulation in a dry climate that the west coast of 
South America affords. 

Along the inner edge of the Desert of Tarapaca, roughly be- 
tween the towns of Tarapaca and Quillagua, Chile, the piedmont 
gravels, sands, silts, and muds extend for over a hundred miles, 
flanking the western Andes and forming a transition belt between 
these mountains and the interior basins of the coast deseft. The 
silts and muds constitute the outer fringe of the piedmont and 
are interrupted here and there where sands are blown upon them 
from the higher portions of the piedmont, or from the desert 
mountains and plains on the seaward side. Practically no rain 
falls upon the greater part of the desert and the only water it re- 
ceives is that borne to it by the piedmont streams in the early 
summer, from the rains and melted snows of the high plateau and 
mountains to the eastward. These temporary streams spread 
upon the outer edge of the piedmont a wide sheet of mud and silt 
which then dries and becomes cracked, the curled and warped 
plates retaining their character until the next wet season or until 
covered with wind-blown sand. The wind-driven sand fills the 
cracks in the muds and is even drifted under the edges of the up- 
curled plates, filling the spaces completely. Over this combined 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 261 

fluvial and seolian deposit is spread the next layer of mud, -which 
frequently is less extensive than the earlier deposits, thus giving 
abundant opportunity for the observation of the exact manner of 
burial of the older sand-covered stratum. 

Now while the alternations are as marked in Peru as in Chile, 
it is noteworthy that the Tertiary material in Peru is not only 
coarse throughout, even to the farthest limits of the piedmont, 
but also that the alternating beds are thick. Moreover, there are 
only the most feeble evidences of wind action in the lowermost 
Tertiary series. I was prepared to find curled plates, wind-blown 
sands, and muds and silts, but they are almost wholly absent. It 
is, therefore, concluded that the dryness was far less extreme than 
it is today and that full streams of great competency flowed vigor- 
ously down from the mountains and carried their loads to the in- 
ner border of the Coast Eange and in places to the sea. 

The fact that the finer material is sandy, not clayey or silty, 
that it almost equals in thickness the coarser layers, and that its 
distribution appears to be co-extensive with the coarser, warrants 
the conclusion that it too was deposited by competent streams of 
a type far different from the withering streams associated with 
piedmont deposits in a thoroughly arid climate like that of today. 
Both in. the second Tertiary series and on the present surface are 
such clear examples of deposits made in a drier climate as to leave 
little doubt that the earliest of the Tertiary strata of the Majes 
Valley were deposited in a time of far greater rainfall than the 
present. It is further concluded that there was increasing dry- 
ness, as shown by hundreds of feet of wind-blown sand near the 
top of the section. But the growing dryness was interrupted by 
at least one period of greater precipitation. Since that time there 
has been a return tothe dry climate of a former epoch. 

Uplift and erosion of the earliest of the Tertiary deposits of 
the Majes Valley is indicated in two ways: (1) by the deformed 
■character of the beds, and (2) by the ensuing coarse deposits 
which were derived from the invigorated streams. Without 
strong deformations it would not be possible to assign the in- 
creased erosion so confidently to uplift; with the coarse deposits 



262 THE ANDES OF SOUTHERN PERU 

that succeed the unconformity Ave have evidence of accumulatiou 
under conditions of renewed uplift in the mountains and of full 
streams competent to remove the increasing load. 

It is in the character of the sediments toward the top of the 
Tertiary that we have the clearest evidence of progressive desic- 
cation of the climate of the region. The amount of wind-blown 
material steadily increases and the uppermost five hundred feet is 
composed predominantly, and in places exclusively, of this ma- 
terial. The evidences of wind action lie chiefly in the fine (in 
places fluffy) nature of the deposits, their uniform character, and 
in the tangency of the layers with respect to the surface on which 
they were deposited. There are three diagnostic structural fea- 
tures of great importance : the very steep dip of the fine laminae ; 
the peculiar and harmonious blending of their contacts ; the man- 
ner in Avhich the highly inclined laminae cut off and succeed each 
other, whereby quite bewildering changes in the direction of dip 
of the inclined beds are brought about on any exposed plane. 
Some of these features require further discussion. 

It is well known that the front of a sand dune generally con- 
sists of sand deposited on a slope inclined at the angle of repose, 
say between 30° and 35°, and rolled into place up the long back 
slope of the dune by the wind. It has not, however, been gener- 
ally recognized that the angle of repose may be exceeded (a) when 
there exists a strong back eddy or (b) when the wind blows vio- 
lently and for a short time in the opposite direction. In either case 
sand is carried up the short steep slope of the dune front and 
accumulated at an angle not infrequently running up to 43° and 
48° and locally, and under the most favorable circumstances, in 
excess of 50°. The conditions under which these steep angles are 
attained are undoubtedly not universal, but they can be found in 
some parts of almost any desert in the world. They appear not 
to be present where the sand grains are of uniform size through- 
out, since that leads to rolling. They are found rather where there 
is a certain limited variation in size that promotes packing. 
Packing and the development of steep slopes are also facilitated 
in parts of the coastal desert of Peru by a cloud canopy that hangs 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 263 

over the desert in the early morning, that in the most favorable 
places moistens even the dune surfaces and that has least penetra- 
tion on the steep semi-protected dune fronts. Sand later blown 
up the dune front or rolled down from the dune crest is en- 
couraged to remain near the cornice on an abnormally steep slope 
by the attraction which the slightly moister sand has for the dry 
grains blown against it. Since dunes travel and since their front 
layers, formed on steep slopes, are cut olf to the level of the sur- 
face in the rear of the dune, it follows that the steepest dips in 
exposed sections are almost always less than those in existing 
dunes. Exceptions to the rule will be noted in filled hollows not 
re-excavated until deeply covered by wind-blown material. These, 
re-exposed at the end of a long period of wind accumulation, may 
exhibit even the maximum dips of the dune cornices. Such will 
be conspicuously the case in sections in aggraded desert deposits. 
On the border of the Majes Valley, from 400 to 500 feet of wind- 
accumulated deposits may be observed, representing a long period 
of successive dune burials. 

The peculiar blending of the contact lines of dune laminae, re- 
lated to the tangency commonly noted in dune accumulations, is 
apparently due to the fact that the wind does not require a graded 
surface to work on, but blows uphill as well as down. It is pres- 
ent on both the back-slope and the front-slope deposits. Its finest 
expression appears to be in districts where the dune material was 
accumulated by a violent wind whose effects the less powerful 
winds could not destroy. 

It is to the ability of the wind to transport material against, 
as well as with, gravity, that we owe the third distinct quality of 
dune material, the succession of flowing lines, in contrast to the 
succession of now flat-lying now steeply inclined beds character- 
istic of cross-bedded material deposited by water. One dune trav- 
els across the face of the country only to be succeeded by another." 
Even if wind aggradation is in progress, the plain-like surface in 
the rear of a dune may be excavated to the level of steeply inclined 

' The best photograph of this condition which I have yet seen is in W. Sievers, SUd- 
und Mittelamerika, second ed., 1914, Plate 15, p. 358. 



264 THE ANDES OF SOUTHERN PERU 

beds upon whose truncated outcrop other inclined beds are laid, 
Fig. 178. The contrast to these conditions in the case of aggrada- 
tion by water is so clearly and easily inferred that space mil not 
be taken to point them out. It is also true as a corollary to the 
above that the greater part of a body of wind-drifted material 
will consist of cross-bedded layers, and not a series of evenly 
divided and alternating flat-lying and cross-bedded layers which 
result from deposition in active and variable currents of water. 

The caution must of course be observed that wind action and 
water action may alternate in a desert region, as already de- 
scribed in Tarapaca in northern Chile, so that the whole of a de- 
posit may exhibit an alternation of cross-bedded and flat-lying lay- 
ers ; but the former only are due to wind action, the latter to water 
action. 

Finally it may be noted that the sudden, frequent, and diversi- 
fied dips in the cross-bedding are peculiarly characteristic of mnd 
action. Although one sees in a given cross-section dips apparently 
directed only toward the left or the right, excavation will supply 
a third dimension from which the true dips may be either ob- 
served or calculated. These show an almost infinite variety of 
directions of dip, even in restricted areas, a condition due to the 
following causes : 

(1) the curved fronts of sand dunes, which produce dips con- 
centric with respect to a point and ranging through 180° of arc; 
(2) the irregular character of sand dunes in many places, a con- 
dition due in turn to (a) the changeful character of the strong 
wind (often not the prevailing wind) to which the formation of 
the dunes is due, and (b) the influence of the local topography 
upon wind directions within short distances or upon winds of 
different directions in which a slight change in wind direction 
is followed by a large change in the local currents; (3) the fact 
that all combinations are possible between the erosion levels of 
the wind in successive generations of dunes blown across a given 
area, hence any condition at a given level in a dune may be com- 
bined with any other condition of a succeeding dune; (4) varia- 
tions in the sizes of successive dunes will lead to further contrasts 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 265 




Fig. 178 — Plan and cross-sections of superimposed sand dunes of conventional 
outline. In the sections, dune A is supposed to have left only a small 
basal portion to be covered by dune B. In the same way dune has advanced to cover 
both A and B. The basal portions that have remained are exaggerated vertically in 
order to display the stratification. It is obviously not necessary that the dunes should 
all be of the same size and shape and advancing in the same direction in order to 
have the tangential relations here displayed. Nor need the aggrading material be 
derived from true dunes. The results would be the same in the case of sand drifts with 
their associated wind eddies. All bedded wind-blown deposits would have the same 
general relations. No two successive deposits, no matter from what direction the 
successive drifts or dunes travel, would exactly correspond in direction and amount 
of dip. 



266 THE ANDES OF SOUTHERN PERU 

not only in the scale of the features but also in the direction and 
amount of the dips. 

Finally, we may note that a section of dune deposits has a dis- 
tinctive feature not exhibited by water deposits. If the foreset 
beds of a cross-bedded water deposit be exposed in a plane 
parallel to the strike of the beds, the beds will appear to be hori- 
zontal. They could not then be distinguished from the truly 
horizontal beds above and below them. But the conditions of \\ind 
deposition we have just noted, and chiefly the facts expressed by 
Fig. 178, make it impossible to select a position in which both 
tangency^and irregular dips are not well developed in a wind de- 
posit. I believe that Ave have in the foregoing facts and inferences 
a means for the definite separation of these two classes of de- 
posits. Difficulties will arise only when there is a quick succession 
of wind and water action in time, or where the wind produces 
powerful and persistent effects without the actual formation of 
dunes. 

The latest known deposits in the coastal region are found sur- 
mounting the terrace tops along the coast between Camana and 
Quilca, where they form deposits several hundred feet thick in 
places. The age of these deposits is determined by fossil evidence, 
and is of extraordinary interest in the determination of the age of 
the great terraces upon which they lie. They consist of alternating 
beds of coarse and fine material, the coarser increasing in thick- 
ness and frequency toward the bottom of the section. It is also 
near the bottom of the section that fossils are now found; the 
higher members are locally saline and throughout there is a 
marked inclination of the beds toward the present shore. The de- 
posits appear not to have been derived from the underlying gran- 
ite-gneiss. They are distributed most abundantly near the mouths 
of the larger streams, as near the Vitor at Quilca, and the Majes 
at Camana. Elsewhere the terrace summit is swept clean of 
waste, except where local clay deposits lie in the ravines, as back 
of Mollendo and where "tierras blancas" have been accumulated 
by the wind. 

These coastal deposits were laid down upon a dissected ter- 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 267 

race up to five miles in width. The degree of dissection is varia- 
ble, and depends upon the relation of the through-flowing streams 
to the Coast Kange. The Vitor and the Majes have cut down 
through the Coast Eange, and locally removed the terrace ; smaller 
streams rising on the flanks of the Coast Range either die out 
near the foot of the range or cross it in deep and narrow valleys. 
The present drainage on the seaward slopes of the Coast Range 
is entirely ineffective in reaching the sea, as was seen in 1911, the 
wettest season known on the coast in years and one of the wettest 
probably ever observed on this coast by man. 

In consequence of their deposition on a terrace that ranges in 
elevation from zero to 1,500 feet above sea level, the deposits of 
the coast are very irregularly disposed. But in consequence of 
their great bulk they have a rather smooth upper surface, grada- 
tion having been carried to the point where the irregularities of 
the dissected terrace were smoothed out. Their general uniform- 
ity is broken where streams cross them, or where streams crossed 
them during the wetter Pleistocene. Their elevation, several hun- 
dred feet above sea level, is responsible for the deep dissection 
of their coastal margin, where great cliffs have been cut. 

PLEISTOCENE 

The broad regional uplift of the Peruvian Andes in late Ter- 
tiary and in Pleistocene times carried their summits above the 
level of perpetual snow. It is still an open question whether or not 
uplift was sufficiently great in the early Pleistocene to be in- 
fluenced by the first glaciations of that period. As yet, there are 
evidences of only two glacial invasions, and both are considered 
late events on account of the freshness of their deposits and the 
related topographic forms. The coarse deposits — nearly 500 feet 
thick — that form the top of the desert section described above 
clearly indicate a wetter climate than prevailed during the 
deposition of the several hundred feet of wind-blown deposits be- 
neath them. But if our interpretation be correct these deposits 
are of late Tertiary age, and their character and position are 
taken to indicate climatic changes in the Tertiary. They may 



268 THE ANDES OF SOUTHERN PERU 

have been the mild precursors of the greater climatic changes of 
glacial times. Certain it is that they are quite unlike the mass 
of the Tertiary deposits. On the other hand they are separated 
from the deposits of known glacial age by a time interval of great 
length — an epoch in which was cut a benched canyon nearly a mile 
deep and three miles wide. They must, therefore, have been 
formed when the Andes were thousands of feet lower and unable 
to nourish glaciers. It was only after the succeeding uplifts had 
raised the mountain crests well above the frost line that the rec- 
ords of oscillating climates were left in erratic deposits, troughed 
valleys, cliff ed cirques and pinnacled divides. 

The glacial forms are chiefly at the top of the country; the 
glacial deposits are chiefly in the deep valleys that were carved 
before the colder climate set in. The rock waste ground up by 
the ice was only a small part of that delivered to the streams in 
glacial times. Everywhere the wetter climate resulted in the 
partial stripping of the residual soil gathered upon the smooth 
mature slopes formed during the long Tertiary cycle of erosion. 
This moving sheet of waste as well as the rock fragments carried 
away from the glacier ends were stre^\^l along the valley floors, 
forming a deep alluvial fill. Thereby the canyon floors were ren- 
dered habitable. 

In the chapters on human geography we have already called 
attention to the importance of the U-shaped valleys carved by the 
glaciers. Their floors are broad and relatively smooth. Their 
walls restrain the live stock. They are sheltered though lofty. 
But all the human benefits conferred by ice action are insig- 
nificant beside those due to the general shedding of waste from 
the cold upper surfaces to the warm levels of the valley floors. 
The alluvium-filled valleys are the seats of dense populations. In 
the lowest of them tropical and sub-tropical products are raised, 
like sugar-cane and cotton, in a soil that once lay on the smooth 
upper slopes of mountain spurs or that was ground fine on the bed 
of an Alpine glacier. 

The Pleistocene deposits fall into three well-defined groups: 
(1) glacial accumulations at the valley heads, (2) alluvial deposits 




Fig. 179 — Snow fields on the summit of the Cordillera Vilcapampa near Ollantay- 
tambo. A huge glacier once lay in the steep canyon in the background and descended 
to the notched terminal moraine at the canyon mouth. In places the glacier was 
over a thousand feet thick. From the terminal moraine an enormous alluvial fan extends 
forward to the camera and to the opposite wall of the Urubamba Valley. It is' 
confluent with other fans of the same origin. See Fig. 180. In the foreground are 
flowers, shrubs, and cacti. A few miles below Urubamba at 11,500 feet. 




Fig. 180. 




Fig. 181. 



Fig. 180 — Urubamba Valley between Ollantaytambo and Torontoy, showing (1) 
more moderate upper slopes and steeper lower slopes of the two-cyole mountain spurs; 
(2) the extensive alluvial deposits of tho valley, consisting chielly of conlluent alluvial 
fans heading in the glaciated mountains on the left. See Fig. 17!>. 

Fig. 181 — Glacial features of the Central Ranges (see Fig. 204). Huge lateral 
moraines built by ice streams tributary to the main vallej' north of Chuquibiinibilla. 
That the tributaries persisted long after the main valley became free of ice is shown 
by the descent of the lateral moraines over the steep border of the main valley and 
down to the floor of it. 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 269 

in the valleys, and (3) lacustrine deposits formed on the floors of 
temporary lakes in inclosed basins. Among these the most varia- 
ble in form and composition are the true glacier-laid deposits at 
the valley heads. The most extensive are the fluvial deposits ac- 
cumulated as valley fill throughout the entire Andean realm. 
Though important enough in some respects the lacustrine deposits 
are of small extent and of rather local significance. Practically 
none of them fall within the field of the present expedition; hence 
we shall describe only the first two classes. 

The most important glacial deposits were accumulated in the 
eastern part of the Andes as a result of greater precipitation, a 
lower snowline, and catchment basins of larger area. In- the 
Cordillera Vilcapampa glaciers once existed up to twelve and fif- 
teen miles in length, and those several miles long were numerous 
both here and throughout the higher portions of the entire Cordil- 
lera, save in the belt of most intense volcanic action, which coin- 
cides with the driest part of the Andes, where the glaciers were 
either very short or wanting altogether. 

Since vigorous glacial action results in general in the cleaning 
out of the valley heads, no deposits of consequence occur in these 
locations. Down valley, however, glacial deposits occur in the 
form of terminal moraines of recession and ground moraines. 
The general nature of these deposits is now so well known that 
detailed description seems quite unnecessary except in the case 
of unusual features. 

It is noteworthy that the moraines decrease in size up valley 
since each valley had been largely cleaned out by ice action before 
the retreat of the glacier began. Each lowermost terminal 
moraine is fronted by a great mass of unsorted coarse bowldery 
material forming a fill in places several hundred feet thick, as be- 
low Choquetira and in the Vilcapampa Valley between Vilca- 
bamba and Puquiura. This bowldery fill is quite distinct from the 
long, gently inclined, and stratified valley train below it, or the 
marked ridge-like moraine above it. It is in places a good half 
mile in length. Its origin is believed to be due to an overriding 
action beyond the last terminal moraine at a time when the ice 



270 THE ANDES OF SOUTHERN PERU 

was well charged with debris, au overriding not marked by 
morainal accumulations, chiefly becaiise the ice did not maintain 
an extreme position for a long period. 

In the vicinity of the terminal moraines the alluvial valley fill 
is often so coarse and so unorganized as to look like till in the cut 
banks along the streams, though its alluvial origin is always 
shoAvn by the topographic form. This characteristic is of special 
geologic interest since the form may be concealed through deposi- 
tion or destroyed by erosion, and no condition but the structure 
remain to indicate the manner of origin of the deposit. In such 
an event it would not be possible to distinguish between alluvium 
and till. The gravity of the distinction appears when it is knoAvn 
that such apparently unsorted alluvium maj^ extend for several 
miles forward of a terminal moraine, in the shape of a wide- 
spreading alluvial fan apparently formed under conditions of ex- 
tremely rapid aggradation. I suppose it would not be doubted in 
general that a section of such stony, bowldery, unsorted material 
two miles long would have other than a glacial origin, yet such 
may be the case. Indeed, if, as in the Urubamba Valley, a future 
section should run parallel to the valley across the heads of a 
great series of fans of similar composition, topographic form, and 
origin, it would be possible to see many miles of such material. 

The depth of the alluvial valley fill due to tributary fan ac- 
cumulation depends upon both the amount of the material and the 
form of the valley. Below Urubamba in the Urubamba Valley a 
fine series is displayed, as shown in Fig. ISO. The fans head in 
valleys extending up to snow-covered summits upon whose flanks 
living glaciers are at work today. Their heads are now crowned 
by terminal moraines and both moraines and alluvial fans are in 
process of dissection. The height and extent of the moraines and 
the allmial fans are in rough proportion and in turn reflect the 
height, elevation, and extent of the valley heads which served as 
fields of nourishment for the Pleistocene glaciers. "Where the fans 
were deposited in narrow valleys the efTect was to increase the 
thickness of the deposits at the expense of their area, to dam the 
drainage lines or displace them, and to so load the streams that 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 271 



they have not yet cleared their beds after thousands of years of 
work under torrential conditions. 

Below Urubamba the alluvial fans entering the main valley 
from the east have pushed the river against its western valley 
wall, so that the river flows on one side against rock and on the 
other against a hundred feet of stratified material. In places, as 
at the head of the narrows on the valley trail to OUantaytambo, 
a flood plain has been formed in front of the scarp cut into the 
alluvium, while the edge of the dissected alluvial fans has been 
sculptured into erosion forms resembling bad-lands topography. 
On the western side of the valley the alluvial fans are very small, 
since they are due to purely local accumulations of waste from 
the edge of the plateau. Glaciation has here displaced the river. 
Its effects will long be felt in the disproportionate erosion of the 
western wall of the valley. 

By far the most interesting of the deposits of glacial time are 
those laid down on the valley floors in the form of an alluvial fill. 
Though such deposits have 
greater thickness as a rule 
near the nourishing mo- 
raines or bordering allu- 
vial fans at the lower ends 
of the valleys, they are 
everywhere important in 
amount, distinctive in topo- 
graphic form, and of amaz- 
ingly wide extent. They 
reach far into and possibly 
across the Amazon basin. 




Fia. 182 — Dissected alluvial fans on the 
border of tlie Urubamba Valley near Hacienda 
Chinche. A characteristic feature of the 
valleys of the Peruvian Andes below the zone 
of glaciation but within the limits of its ag- 
graditional effects. Through alluviation the 
valleys and basins of the Andean Cordillera, 
and vast areas of the great Amazon plains cast 
of it, felt tlie effects of the glacial conditions 
of a past age. 



they form a distinct though 
small piedmont fringe along the eastern base of the Andes, and 
they are universal throughout the Andean valleys. That a deposit 
of such volume — many times greater than all the material accumu- 
lated in the form of high-level alluvial fans or terminal moraines 
— should originate in a tropical land in a region that suffered but 
limited Alpine glaciation vastly increases its importance. 



272 



THE ANDES OF SOUTHERN PERU 




•■■."-.■.•.? VAUIV FILL 



The fill is composed of both, fine and coarse material laid dowa 
by water in steep valley floors to a depth of many feet. It breaks 
the steep slope of each valley, forming terraces with pronounced 
frontal scarps facing the river. On the raw bluffs at the scarps 
made by the encroaching stream good exposures are afforded. 
At Chinche in the Urubamba Valley above Santa Ana, the material 
is both sand and clay with an important amount of gravel laid 
down Avith steep valleyward inclination and under torrential con- 
ditions; so that \vithin a 
given bed there may be an 
apparent absence of lamina- 
tion. Almost identical con- 
ditions are exhibited fre- 
, quently along the railway to 
Cuzco in the Vilcanota Val- 
ley. The material is mixed 
sand and gravel, here and 
there running to a bowldery 
or stony mass where acces- 
sions have been received 
from some source nearby. 
It is modified along its mar- 
gin not only in topographic 
form but also in composition 
by small tributary alluvial 
fans, though these in general 
constitute but a small part of the total mass. At Cotahuasi, Fig. 
29, there is a remarkable fill at least four hundred feet deep in 
many places where the river has exposed fine sections. The 
depth of the fill is, however, not determined by the height of the 
erosion bluffs cut into it, since the bed of the river is made of the 
same material. The rock floor of the valley is probably at least 
an additional hundred feet below the present level of the river. 

Similar conditions are well displayed at Huadquina, where a 
fine series of terraces at the lower end of the Torontoy Canyon 
break the descent of the environing slopes ; also in the Urubamba 



Fig. 183 — Two-cj'cle slopes and alluvial fill 
between Huichiliua and Chuquibambilla. The 
steep slopes on the inner valley border are in 
many places vertical and rock cliffs are every- 
where abundant. Mature slopes have their 
greatest development here between 13,500 and 
15,000 feet (4,110 to 4,570 m.). Steepest ma- 
ture slopes run from 15° to 21°. Least steep 
are the almost level spur summits. The depths 
of the valley fill must be at least 300, and may 
possibly be 500 feet. The break between valley 
fill and steep slopes is most pronounced where 
the river runs along the valley wall or under- 
cuts it; least pronounced where alluvial fans 
spread out from the head of some ravine. It 
is a bowldery, stony fill almost everywhere 
terraced and cultivated. 



PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 273 

Valley below Eosalina, and again at the edge of the mountains at 
the Pongo de Mainique. It is exhibited most impressively in the 
Majes Valley, where the bordering slopes appear to be buried 
knee-deep in waste, and where from any reasonable downward ex- 
tension of rock walls of the valley there would appear to be at 
least a half mile of it. It is doubtful and indeed improbable that 
the entire fill of the Majes Valley is glacial, for during the Pliocene 
or early Pleistocene there was a submergence which gave op- 
portunity for the partial filling of the valley with non-glacial al- 
luvium, upon which the glacial deposits were laid as upon a flat 
and extensive floor that gives an exaggerated impression of their 
depth. However, the head of the Majes Valley contains at least 
six hundred feet and probably as much as eight hundred feet of 
alluvium now in process of dissection, whose coarse texture 
and position indicates an origin under glacial conditions. The 
fact argues for the great thickness of the alluvial material of the 
lower valley, even granting a floor of Pliocene or early Pleistocene 
sediments. The best sections are to be found just below Chu- 
quibamba and again about halfway between that city and Aplao, 
whereas the best display of the still even-floored parts of the 
valley are between Aplao and Cantas, where the braided river 
still deposits coarse gravels upon its wide flood plain. 



CHAPTER XVI 
GLACIAL FEATURES 

THE SNOWLINE 

South Ameeica is classical ground in the study of tropical 
snowlines. The African mountains that reach above the snowline 
in the equatorial belt — Euwenzori, Kibo, and Kenia — have only 
been studied recently because they are remote from the sea and 
surrounded by bamboo jungle and heavy tropical forest. On the 
other hand, many of the tropical mountains of South America lie 
so near the west coast as to be visible from it and have been 
studied for over a hundred years. From the days of Humboldt 
(1800) and Boussingault (1825) down to the present, observations 
in the Andes have been made by an increasing number of scientific 
travelers. The result is a large body of data upon which compara- 
tive studies may now be profitably undertaken. 

Like scattered geographic observations of many other kinds, 
the earlier studies on the snowline have increased in value with 
time, because the snowline is a function of climatic elements that 
are subject to periodic changes in intensity and cannot be under- 
stood by reference to a single observation. Since the discovery 
of physical proofs of climatic changes in short cycles, studies 
have been made to determine the direction and rate of change of 
the snowline the world over, with some very striking results. 

It has been found ^ that the changes run in cycles of from 
thirty to thirty-five years in length and that the northern and 
southern hemispheres appear to be in opposite phase. For ex- 
ample, since 1885 the snowline in the southern hemisphere has 
been decreasing in elevation in nine out of twelve cases by the 
average amount of nine hundred feet. With but a single excep- 

^ Paschinger, Die Schneegrenze in yerschiedenen Klimaten. Peter. Mitt. 
Erganz'heft, Nr. 173. 1912, pp. 92-93. 

374 



GLACIAL FEATURES 275 

tion, the snowline in tlie nortliern hemisphere has been rising 
since 1890 with an average increase of five hundred feet in sixteen 
cases. To be sure, we must recognize that the observations upon 
which these conclusions rest have unequal value, due both to per- 
sonal factors and to differences in instrumental methods, but that 
in spite of these tendencies toward inequality they should agree 
in establishing a general rise of the snowline in the northern 
hemisphere and an opposite effect in the southern is of the high- 
est significance. 

It must also be realized that snowline observations are alto- 
gether too meager and scattered in view of the abundant op- 
portunities for making them, that they should be standardized, 
and that they must extend over a much longer period before they 
attain their full value in problems in climatic variations. Once 
the possible significance of snowline changes is appreciated the 
number and accuracy of observations on the elevation and local 
climatic relations of the snowline should rapidly increase. 

In 1907 I made .a number of observations on the height of the 
snowline in the Bolivian and Chilean Andes between latitudes 17° 
and 20° south, and in 1911 extended the work northward into the 
Peruvian Andes along the seventy-third meridian. It is proposed 
here to assemble these observations and, upon comparison with 
published data, to make a few interpretations. 

From Central Lagunas, Chile, I went northeastward via Pica 
and the Huasco Basin to Llica, Bolivia, crossing the Sillilica Pass 
in May, 1907, at 15,750 feet (4,800 m.). Perpetual snow lay at an 
estimated height of 2,000-2,500 feet above the pass or 18,000 feet 
(5,490 m.) above the sea. Two weeks later the. Huasco Basin, 
14,050 feet (4,280 m.), was covered a half -foot deep with snow and 
a continuous snow mantle extended down to 13,000 feet. Light 
snows are reported from 12,000 feet, but they remain a few hours 
only and are restricted to the height of exceptionally severe win- 
ter seasons (June and early July). Three or four distant snow- 
capped peaks were observed and estimates made of the elevation 
of the snowline between the Cordillera Sillilica and Llica on the 
eastern border of the Maritime Cordillera. All observations 



276 THE ANDES OF SOUTHERN PERU 

agreed in giving an elevation much, in excess of 17,000 feet. In 
general the values run from 18,000 to 19,000 feet (5,490 to 5,790 
m.). Though the bases of these figures are estimates, it should 
be noted that a large part of the trail lies between 14,000 and 
16,000 feet, passing mountains snow-free at least 2,000 to 3,000 
feet higher, and that for general comparisons they have a distinct 
value. 

In the Eastern Cordillera of Bolivia, snow was observed on 
the summit of the Tunari group of peaks northwest of Cocha- 
bamba. Steinmann, who visited the region in 1904, but did not 
reach the summit of the Tunari group of peaks, concludes that 
the limit of perpetual snow should be placed above the highest 
point, 17,300 (5,270 m.) ; but in July and August, 1907, I saw a 
rather extensive snow cover over at least the upper 1,000 feet, and 
what appeared to be a very small glacier. Certain it is that the 
Cochabamba Indians bring clear blue ice from the Tunari to the 
principal hotels, just as ice is brought to Cliza from the peaks 
above Arani. On these grounds I am inclined to place the snow- 
line at 17,000 feet (5,180 m.) near the eastern border of the 
Eastern Cordillera, latitude 17° S. At 13,000 feet, in July, 1907, 
snow occurred in patches only on the pass called Abre de Malaga, 
northeast of Colomi, 13,000 feet, and fell thickly while Ave were 
descending the northern slopes toward Corral, so that in the early 
morning it extended to the cold timber line at 10,000 feet. In a 
few hours, however, it had vanished from all but the higher and 
the shadier situations. 

In the Vilcanota knot above the divide between the Titicaca 
and Vilcanota hydrographic systems, the elevation of the snow- 
line was 16,300-f feet (4,970 m.) in September, 1907. On the 
Cordillera Eeal of Bolivia it is 17,000 to 17,500 feet on the north- 
east, but falls to 16,000 feet on the southwest above La Paz. In 
the first week of July, 1911, snow fell on the streets of Cuzco 
(11,000 feet) and remained for over an hour. The heights north 
of San Geronimo (16,000 feet) miss the limit of perpetual snow 
and are snow-covered only a few months each year. 

In taking observations on the snowline along the seventy-third 



GLACIAL FEATURES 277 

meridian I was fortunate enough to have a topographer the 
heights of whose stations enabled me to correct the readings of 
my aneroid barometer whenever these were taken off the line of 
traverse. Furthermore, the greater height of the passes — 15,000 
to 17,600 feet — brought me more frequently above the snowline 
than had been the case in Bolivia and Chile. More detailed ob- 
servations were made, therefore, not only upon the elevation of 
the snowline from range to range, but also upon the degree of 
canting of the snowhne on a given range. Studies were also made 
on the effect of the outline of the valleys upon the extent of the 
glaciers, the influence on the position of the snowline of mass ele- 
vation, precipitation, and cloudiness. 

Snow first appears at 14,500 feet (4,320 m.) on the eastern 
flanks of the Cordillera Vilcapampa, in 13° south latitude. East 
of this group of ridges and peaks as far as the extreme eastern 
border of the mountain belt, fifty miles distant, the elevations 
decrease rapidly to 10,000 feet and lower, with snow remaining 
on exceptionally high peaks from a few hours to a few months. 
In the winter season snow falls now and then as low as 11,500 feet, 
as in the valley below Vilcabamba pueblo in early September, 
1911, though it vanishes like mist with the appearance of the sun 
or the warm up-valley winds from the forest. Storms gather 
daily about the mountain summits and replenish the perpetual 
snow above 15,000 feet. In the first pass above Puquiura we en- 
countered heavy snow banks on the northeastern side a hundred 
feet below the pass (14,500 feet), but on the southwestern or lee- 
ward side it is five hundred feet lower. This distribution is ex- 
plained by the lesser insolation on the southwestern side, the im- 
mediate drifting of the clouds from the -windward to the leeward 
slopes, and to the mutual intensification of cause and effect by 
topographic changes such as the extension of collecting basins and 
the steeping of the slopes overlooking them with a correspond- 
ing increase in the duration of shade. 

It is well known that with increase of elevation and there- 
fore of the rarity of the air there is less absorption of the sun's 
radiant energy, and a corresponding increase in the degree of in- 



278 THE ANDES OF SOUTHERN PERU 

solation. It f oUoavs, therefore, that at high altitudes the contrasts 
between sun and shade temperatures will increase. Frankland - 
has shown that the increase may run as high as 500 per cent be- 
tween 100 to 10,000 feet above the sea. I have noted a fall of tem- 
perature of 15° F. in six minutes, due to the obscuring of the sun 
by cloud at an elevation of 16,000 feet above Huichihua in the 
Central Eanges of Peru. Since the sun shines approximately 
half the time in the snow-covered portions of the mountains and 
since the tropical Andes are of necessity snow-covered only at 
lofty elevations, this contrast between shade and sun tempera- 
tures is by far the most powerful factor influencing differences in 
elevation of the snowline in Peru. 

To the drifting of the fallen snow is commonly ascribed a 
large portion of this contrast. I have yet to see any evidence of 
its action near the snowline, though I have often observed it, 
especially under a high wind in the early morning hours at con- 
siderable elevations above the snowline, as at the summits of lofty 
peaks. It appears that the lower ranges bearing but a limited 
amount of snow are not subject to drifting because of the wetness 
of the snow, and the fact that it is compacted by occasional rains 
and hail storms. Only the drier snow at higher elevations and 
under stronger winds can be effectively dislodged. 

The effect of unequal distribution of precipitation on the wind- 
ward and leeward slopes of a mountain range is in general to de- 
press the snowline on the windward slopes Avhere the greater 
amount falls, but this may be offset in high altitudes by tempera- 
ture contrasts as in the westward trending Cordillera Vilcapampa, 
where north and south slopes are in opposition. If the Cordillera 
Vilcapampa ran north and south we should have the -windward 
and leeward slopes equally exposed to the sun and the snowline 
would lie at a lower elevation on the eastern side. Among all the 
ranges the slopes have decreasing precipitation to the leeward, 
that is, westerly. The second and third passes, between Arma and 
Choquetira, are snow-free (though their elevations equal those of 

' Hann, Handbook of Climatology, Part 1, trans, by Ward, 1903, p. 232. 



GLACIAL FEATURES 279 

the first pass) because they are to leeward of the border range, 
hence receive less precipitation. The depressive effect of increased 
precipitation on the snowline is represented by A-B, Fig. 184; in 
an individual range the effect of heavier precipitation may be off- 
set by temperature contrasts between shady and sunny slopes, as 
shown by the line a-b in the same figure. 

The degree of canting of the snowline on opposite slopes of 
the Cordillera Vilcapampa varies between 5° and 12°, the higher 
value being represented four hours southwest of Arma on the 
Choquetira trail, looking ^ ^^__^ ^ ^ 

northeast. A general view jk 



& 



IE 



of the Cordillera looking 



& 



east at this point (Fig. 186), 
shows the appearance of the 

snowline as one looks along towaid the north (right) in response to heavier 



Fig. 184 — To illustrate the canting of the 
shows the appearance of the snowline, a-b is the snowline depressed 



the flanks of the range. In 



precipitation. The line a-6 represents a de- 
pression in the opposite direction due to the 
detail the snowline is fur- different degree of insolation on the northern 
,, T , -I -I I (sunny) and southern (shady) slopes. 

ther complicated by topog- 
raphy and varying insolation, each spur having a snow- clad and 
snow-free aspect as shown in the last figure. The degree of dif- 
ference on these minor slopes may even exceed the difference 
between opposite aspects of the range in which they occur. 

To these diversifying influences must be added the effect of 
warm up-valley Avinds that precede the regular afternoon snow 
squalls and that melt the latest fall of snow to exceptionally high 
elevations on both the valley floor and the spurs against which 
they impinge. The influence of the warmer air current is notably 
confined to the heads of those master valleys that run down the 
wind, as in the valley heading at the first pass, Cordillera Vilca- 
pampa, and at the heads of the many valleys terminating at the 
passes of the Maritime Cordillera. Elsewhere the winds are dis- 
sipated in complex systems of minor valleys and their effect is 
too well distributed to be recognized. 

It is clear from the conditions of the problem as outlined on 
preceding pages that the amount of canting may be expressed in 
feet of difference of the snowline on opposite sides of a range or 



280 



THE ANDES OF SOUTHERN PERU 



in degrees. The former method has, heretofore, been employed. 
It is proposed that this method should be abolished and degrees 
substituted, on the following grounds : Let A and B, Fig. 190, rejD- 
resent two mountain masses of unequal area and unequal eleva- 
tion. Let the opposite ends of the snowlines of both figures lie 
1,000 feet apart as between the windward and leeward sides of a 

broad coi'dillera (A), or as 



between the relatively sun- 
nier and relatively shadier 
slopes of individual moun- 
tains or narrow ranges in 
high latitudes or high alti- 
tudes (B). With increasing 
elevation there is increasing 
contrast between tempera- 
tures in sunshine and in 
shade, hence a greater de- 
gree of canting (B). Tend- 
ing toward a still greater 
degree of contrast is the ef- 
fect of the differences in the 
amounts of snowy precipita- 
tion, which are always more 
marked on an isolated and 
lofty mountain summit than 
upon a broad mountain 
mass (1) because in the 
former there is a very re- 
stricted area where snow 




Fig. 185 — Glacial features in the Peru- 
vian Andes near Arequipa. Sketclied from a 
railway train, July, 1911. The horizontal 
broken lines represent the lower limit of light 
snow during late June, 1911. There is a fine 
succession of moraines in U-shaped valleys in 
all the mountains of the Arequipa region. A 
represents a part of Chacchani northwest of 
Arequipa; B is looking south by east at the 
northwest end of Chachani near Pampa de 
Arrieros; also shows the northwest end of 
Chacchani from a more distant point. 



may accumulate, and (2) 
because with increase of elevation there is a rapid and differential 
decrease in both the rate of adiabatic cooling and the amount of 
water vapor; hence the snow-producing forces are more quickly 
dissipated. 

Furthermore, the leeward side of a lofty mountain not only 
receives much less snow proportionally than the leeward side of 











Fig. 186. 




Fig. 187. 

Fig. 186 — Canted snowline in the Cordillera Vileapampa between Arma and 
Choquetird. Looking east from 13,500 feet. 

Fig. 187 — Glacial topograph}' between Lambrama and Antabamba in the Central 
Ranges. A recent fall of snow covers the foreground. The glaciers are now almost 
extinct and their action is confined to the deepening and steepening of the cirques at 
the valley heads. 




Fig. 188. 




Fig. 189. 



Fig. 188 — Asymmetrical peaks In the Central Ranges between Antabanilia and 
Lambrama. Tlie snow-filled liollows in the pliotograph face away from the sun — that 
is, south — and have retained snow since tlie ghicial epoch; while the northern slopes 
are snow-free. There is no true glacial ice and the continued cir<iue recession is due 
to nivation. 

Fig. 180 — Glacial topograpliy north of the divide on the sevcnty-tliird meridian. 
Maritime Cordillera. Looking downstream at an elevation of 10,500 feet (5,030 m.). 



GLACIAL FEATURES 281 

a lower mountain, but also loses it faster on account of the 
smaller extent of surface upon which it is disposed and the pro- 
portionally larger extent of counteractive, snow-free surface 
about it. Among the volcanoes of Ecuador are many that show 
differences of 500 feet in snowline elevation on windward and lee- 
ward (east) slopes and some, as for example Chimborazo, that 
exhibit differences of 1,000 feet. The latter figure also expresses 

iOML^-'^--K R° gradient 



Fig. 190 — To illustrate the difference in the degree of canting of the snowline on 
large and on small nioimtain masses. 

the differences in the broad Cordillera Vilcapampa and in the 
Maritime Cordillera, though the rate of canting as expressed in 
degrees is much greater in the case of the western mountains. 

The advantages of the proposed method of indicating the de- 
gree of canting of the snowline lie in the possibility thus afforded 
of ultimately separating and expressing quantitatively the vari- 
ous factors that affect the position of the line. In the Cordillera 
Vilcapampa, for example, the dominant canting force is the dif- 
ference between sun and shade temperatures, while in the vol- 
canoes of Ecuador, where symmetrical volcanoes, almost on the 
equator, have equal insolation on all aspects and the temperature 
contrasts are reduced to a minimum — the differences are owing 
chiefly to varying exposure to the winds. The elusive factors in 
the comparison are related to the differences in area and in ele- 
vation. 

The value of arriving finally at close snowline analyses grows 
out of (1) the possibility of snowline changes in short cycles and 
(2) uncertainty of arriving by existing methods at the snowline 
of the glacial period, whose importance is fundamental in refined 
physiographic studies in glaciated regions with a complex topog- 
raphy. To show the application of the latter point we shall now 



282 THE ANDES OF SOUTHERN PERU 

attempt to determine the snowline of the glacial period in the belt 
of country along the route of the Expedition. 

In the group of peaks shown in Fig. 188 between Lambrama 
and Antabamba, the elevation of the snowline varies from 16,000 
to 17,000 feet (4,880-5,180 m.), depending on the topography and 
the exposure. The determination of the limit of perpetual snow 
was here, as elsewhere along the seventy-third meridian, based 
upon evidences of nivation. It will be observed in Fig. 191 that 
just under the snow banks to the left of the center are streams of 
rock waste which head in the snow. Their size is roughly propor- 
tional to the size of the snow banks, and, furthermore, they are not 
found on snow-free slopes. From these facts it is concluded that 
they represent the waste products of snow erosion or nivation, 
just as the hollows in which the snow lies represent the topo- 
graphic products of nivation. On account of the seasonal and an- 
nual variation in precipitation and temperature — hence in the ele- 
vation of the snowline — it is often difficult to make a correct snow- 
line observation based upon depth and apparent permanence. 
Different observers report great changes in the snowline in short 
intervals, changes not explained by instrumental variations, since 
they are referred to topographic features. It appears to be im- 
possible to rely upon present records for small changes possibly 
related to minor climatic cycles because of a lack of standardiza- 
tion of observations. 

Nothing in the world seems simpler at first sight than an ob- 
servation on the elevation of the snowline. Yet it can be demon- 
strated that large numbers of observers have merely noted the 
position of temporary snow. It is strongly urged that evidences 
of nivation serve henceforth as proof of permanent snow and that 
photographic records be kept for comparison. In this way meas- 
urements of changes in the level of the snowline may be accurately 
made and the snow cover used as a climatic gauge. 

Farther west in the Maritime Cordillera, the snowline rises to 
18,000 feet on the northern slopes of the mountains and to 17,000 
feet on the southern slopes. The top of the pass above Cotahuasi, 
17,600 feet (5,360 m.), was snow-free in October, 1911, but the 



72"4o' 




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ENe.AfJD PTG.BV THE TOPOSRAPHIC ENGRAVING CO. WAPH. [j, f 

Edition of 1916. 



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THE YALE PERUVIAN EXPEDITION OF 1911- 

HIRAM BINGHAM, DIRECTOR 

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GLACIAL FEATURES 283 

snow extended 500 feet lower on the southern slope. The degree 
of canting is extraordinary at this point, single volcanoes only 
1,500 to 2,000 feet above the general level and with bases but a 
few miles in circumference exhibit a thousand feet of difference 
in the snowline upon northern and southern aspects. This 
is to be attributed no less to the extreme elevation of the snow 
(and, therefore, stronger contrasts of shade and sun tempera- 
tures) than to the extreme aridity of the region and the high day- 
time temperatures. The aridity is a factor, since heavy snowfall 
means a lengthening of the period of precipitation in which a 
cloud cover shuts out the sun and a shortening of the period of 
insolation and melting. 

Contrasts between shade and sun temperatures increase with 
altitude but their effects also increase in time. Of two volcanoes 
of equal size and both 20,000 feet above sea level, that one will 
show the greater degree of canting that is longer exposed to the 
sun. The high daytime temperature is a factor, since it tends to 
remove the thinnest snow, which also falls in this case on the side 
receiving the greatest amount of heat from the sun. The high 
daytime temperature is phenomenal in this region, and is owing 
to the great extent of snow-free land at high elevations and yet 
below the snowline, and to the general absence of clouds and the 
thinness of vegetation. 

On approach to the western coast the snowline descends again 
to 17,500 feet on Coropuna. There are three chief reasons for 
this condition. First, the well-watered Majes Valley is deeply 
incised almost to the foot of Coropuna, above Chuquibamba, and 
gives the daily strong sea breeze easy access to the mountain. 
Second, the Coast Eange is not only low at the mouth of the Majes 
Valley, but also is cut squarely across by the valley itself, so that 
heavy fogs and cloud sweep inland nightly and at times completely 
cover both valley and desert for an hour after sunrise. Although 
these yield no moisture to the desert or the valley floor except 
such as is mechanically collected, yet they do increase the precipi- 
tation upon the higher elevations at the valley head. 

A third factor is the size of Coropuna itself. The mountain 



284 THE ANDES OF SOUTHERN PERU 

is not a simple volcano but a composite cone ^vith five main sum- 
mits reaching well above the snowline, the highest to an elevation 
of 21,703 feet (6,615 m.). It measures about 20 miles (32 km.) in 
circumference at the snowline and 45 miles (72 km.) at its base 
(measuring at the foot of the steeper portion), and stands upon 
a great tributary lava plateau from 15,000 to 17,000 feet above 
sea level. Compared mth El Misti, at Arequipa, its volume is 
three times as great, its height two thousand feet more, and its 
access to ocean winds at least thirty per cent more favorable. El 
Misti, 19,200 feet (5,855 m.) has snow down as far as 16,000 feet 
in the wet season and rarely to 14,000 feet, though by sunset a 
fall of snow may almost disappear whose lower limit at sunrise 
was 16,000 feet. Snow may accumulate several thousand feet be- 
low the summit during the wet season, and in such quantities as 
to require almost the whole of the ensuing dry season (March to 
December) for its melting. Northward of El Misti is the massive 
and extended range, Chachani, 20,000 feet (6,100 m.) high; on the 
opposite side is the shorter range called Pichu-Pichu. Snow lies 
throughout the year on both these ranges, but in exceptional sea- 
sons it nearly disappears from Chachani and wholly disappears 
from Pichu-Pichu, so that the snowline then rises to 20,000 feet. 
It is considered that the mean of a series of years would give a 
value between 17,000 and 18,000 feet for the snowline on all the 
great mountains of the Arequipa region.^ This would, however, in- 
clude what is kno-\vn to be temporary snow; the limit of "per- 
petual" snow, or the true snowline, appears to lie about 19,000 
feet on Chachani and above EI Misti, say 19,500 feet. It is also 
above the crest of Pichu-Pichu. The snowline, therefore, appears 
to rise a thousand feet from Coropuna to El Misti, owing chiefly 
to the poorer exposure of the latter to the sources of snowy pre- 
cipitation. 

It may also be noted that the effect of the easy access of the 
ocean winds in the Coropuna region is also seen in the increasing 
amount of vegetation which appears in the most favorable situa- 

• S. I. Bailey, Peruvian Meteorology, 188S-1890. Ann. Astron. Observ. of Har- 
vard Coll., Vol. 39, Pt. I, 1899, pp. 1-3. 



GLACIAL FEATURES 285 

tions. Tlius, along the Salamanca trail only a few miles from the 
base of Coropuna are a few square kilometers of quenigo wood- 
land generally found in the cloud belt at high altitudes; for ex- 
ample, at 14,000 feet above Lambrama and at 9,000 feet on the 
slope below Incahuasi, east of Pasaje. The greater part of the 
growth is disposed over hill slopes and on Ioav ridges and valley 
walls. It is, therefore, clearly unrelated as a whole to the greater 
amount of ground-water with which a part is associated, as along 
the valley floors of the streams that head in the belt of perpetual 
snow. The appearance of this growth is striking after days of 
travel over the barren, clinkery lava plateau to eastward that has 
a less favorable exposure. The quenigo forest, so-called, is of 
the greatest economic value in a land so desolate as the vast arid 
and semi-arid mountain of western Peru. Every passing traveler 
lays in a stock of fire-wood as he rests his beasts at noonday; and 
long journeys are made to these curious woodlands from both 
Salamanca and Chuquibamba to gather fuel for the people of the 
towns. 

NWATION 

The process of nivation, or snow erosion, does not always pro- 
duce visible effects. It may be so feeble as to make no impression 
upon very resistant rock where the snow-fall is light and the 
declivity low. Ablation may in such a case account for almost the 
whole of the snow removed. On strong and topographically 
varied slopes Avhere the snow is concentrated in headwater alcoves, 
there is a more pronounced downward movement of the snow 
masses with more prominent effects both of erosion beneath the 
snow and of accumulation at the border of the snow. In such 
cases the limit of perpetual snow may be almost as definitely 
known as the limit of a glacier. Like glaciers these more power- 
ful snow masses change their limits in response to regional 
changes in precipitation, temperature, or both. It would at first 
sight appear impossible to distinguish between these changes 
through the results of nivation. Yet in at least a few cases it may 
be as readily determined as the past limits of glaciers are inferred 



286 THE ANDES OF SOUTHERN PERU 

from the terminal moraines, still intact, that cross the valley 
floors far below the present limits of the ice. 

In discussing the process of nivation it is necessary to assume 
a sliding movement on the part of the snow, though it is a condi- 
tion in Matthes' original problem in which the nivation idea was 
introduced that the snow masses remain stationary. It is be- 
lieved, however, that Matthes' valuable observations and conclu- 
sions really involve but half the problem of nivation; or at the 
most but one of two phases of it. He has adequately sho^^^l the 
manner in which that phase of nivation is expressed which we find 
at the border of the snow. Of the action beneath the snow he 
says merely: "Owing to the frequent oscillations of the edge and 
the successive exposure of the different parts of the site to frost 
action, the area thus affected will have no well-defined boundaries. 
The more accentuated slopes will pass insensibly into the flatter 
ones, and the general tendency will be to give the drift site a cross 
section of smoothly curved outline and ordinarily concave. ' ' ■* 

From observations on the effects of nivation in valleys, Matthes 
further concludes that "on a grade of about 12 per cent . . . 
neve must attain a thickness of at least 125 feet in order that it 
may have motion,"^ though as a result of the different line of 
observations Hobbs concludes ^ that a somewhat greater thickness 
is required. 

The snow cover in tropical mountains offers a number of solid 
advantages in this connection. Its limits, especially on the Cordil- 
lera Vilcapampa, on the eastern border of the Andes, are subject 
to small seasonal oscillations and the edge of the "perpetual" 
snow is easily determined. Furthermore, it is known from the 
comparatively "fixed quality of tropical climate," as Humboldt 
put it, that the variations of the snowline in a period of years do 
not exceed rather narrow limits. In mid-latitudes on the con- 
trary there is an extraordinary shifting of the margin of the snow 



* F. E. Matthes, Glacial Sculpture of the Bighorn Mountains, Wyoming, Twentieth 
Ann. Rept. U. S. Geol. Surv., 1899-1900, Pt. 2, p. 181. 
" Idem, p. 190. 
° W. H. Hobbs, Characteristics of Existing Glaciers, 1911, p. 22. 




Fig. 191. 




Fig. 192. 



Fig 191 — The "pocked" surface characteristically developed in the zone of light 
nivation. Compare with Fig. 194, showing the effects of heavy nivation. 

Fig. 192 — Steep cirque walls and valleys head in the Central Ranges between 
Lambrama and Chuquibambilla. The snow is here a vigorous agent in transporting 
talus material and soil from all the upper slopes down to the foot of the cirque wall. 




Fig. 193. 




Fig. 194. 



Fig. 193 — Panta Mountain and its glacier system. The talus-covered mass in the 
center (B) is a terminal moraine topped by the dirt-stained glacier that descends 
from the crest. The separate glaciers were formerly united to form a huge ice tongue 
that truncated the lateral spurs and flattened the valley floor. One of its former 
stages is shown by the terminal moraine in the middle distance, breached by a stream, 
and impounding a lake not visible from this point of view. 

Fig. 104 — Recessed southern slopes of volcanoes whose nortliern sUipcs arc prac- 
tically without glacial modifications. Summit of the lava plateau, Maritime Cordillera, 
"Western Peru, between Antabamba and Cotahuasi. 



GLACIAL FEATURES 287 

cover, and a correspondingly wide distribution of the feeble ef- 
fects of nivation. 

Test cases are presented in Figs. 191, 192, and 193, Cordillera 
Vilcapampa, for the determination of the fact of the movement 
of the snow long before it has reached the thickness Matthes or 
Hobbs believes necessary for a movement of translation to begin. 
Fig. 191 shows snow masses occupying pockets on the slope of a 
ridge that was never covered with ice. Past glacial action with 
its complicating effects is, therefore, excluded and we have to deal 
with snow action pure and simple. The pre-glacial surface with 
smoothly contoured slopes is recessed in a noteworthy way from 
the ridge crest to the snowline of the glacial period at least a thou- 
sand feet lower. The recesses of the figure are peculiar in that 
not even the largest of them involve the entire surface from top 
to bottom; they are of small size and are scattered over the entire 
slope. This is believed to be due to the fact that they represent 
the limits of variations of the snowline in short cycles. Below 
them as far as the snowline of the glacial period are larger re- 
cesses, some of which are terminated by masses of waste as exten- 
sive as the neighboring moraines, but disposed in irregular scal- 
lops along the borders of the ridges or mountain slopes in which 
the recesses have been found. 

The material accumulated at the lower limit of the snow cover 
of the glacial period was derived from two sources: (1) from 
slopes and cliffs overlooking the snow, (2) from beneath the snow 
by a process akin to ice plucking and abrasion. The first process 
is well known and resembles the shedding of waste upon a valley 
glacier or a neve field from the bordering cliffs and slopes. Ma- 
terial derived in this manner in many places rolls down a long 
incline of snow and comes to rest at the foot of it as a fringe of 
talus. The snow is in this case but a substitute for a normal mass 
of talus. The second process produces its most clearly recogniza- 
ble effects on slopes exceeding a declivity of 20° ; and upon 30° 
and 40° slopes its action is as well-defined as true glacial action 
which it imitates. It appears to operate in its simplest form as 
if independent of the mass of the snow, small and large snow 



288 THE ANDES OF SOUTHERN PERU 

patches sliowiug essentially the same results. This is the reverse 
of Matthes' conclusion, since he says that though the minimum 
thickness "must vary inversely with the percentage of the grade," 
"the influence of the grade is inconsiderable, " and that the law 
of variation must depend upon additional observation.' 

Let us examine a number of details and the argument based 
upon them and see if it is not possible to frame a satisfactory law 
of variation. 

In Fig. 193 the chief conditions of the problem are set forth. 
Forward from the right-hand peak are snow masses descending 
to the head of a talus (A) Avhose outlines are clearly defined by 
freshly fallen snow. At (B) is a glacier whose tributaries descend 
the middle and left slopes of the picture after making a descent 
from slopes several thousand feet higher and not visible in this 
view. The line beneath the glacier marks the top of the moraine 
it has built up. Moraines farther down valley show a former 
greater extent of the glacier. Clearly the talus material at (A) 
was accumulated after the ice had retreated to its present posi- 
tion. It Avill be readily seen from an inspection of the photograph 
that the total amount of material at (A) is an appreciable fraction 
of that in the moraine. The ratio appears to be about 1 : 8 or 1 : 10. 
I have estimated that the total area of snow-free surface about 
the snowfields of the one is to that of the other as 2:3. The 
gradients are roughly equivalent, but the volume of snow in the 
one case is but a small fraction of that in the other. It will be 
seen that the snow masses have recessed the mountain slopes at A 
and formed deep hollows and that the hollowing action appears to 
be most effective where the snow is thickest. 

Summarizing, we note first, that the roughly equivalent factors 
are gradient and amount of snow-free surface; second, that the 
unequal factors are (a) accumulated waste, (b) degree of recess- 
ing, and (c) the degree of compacting of snow into ice and a cor- 
responding difference in the character of the glacial agent, and 
(d) the extent of the snow cover. The direct and important 

' Op. eit., p. 286. Reference on p. 190. 



GLACIAL FEATURES 289 

relation of the first two unequal factors to the third scarcely need 
be pointed out. 

We have then an inequality in amount of accumulated material 
to be explained by either an inequality in the extent of the snow 
and therefore an inequality of snow action, or an inequality due 
to the presence of ice in one valley and not in the other, or by 
both. It is at once clear that if ice is absent above (A) and the 
mountain slopes are recessed that snow action is responsible for 
it. It is also recognized that whatever rate of denudation be as- 
signed to the snow-free surfaces this rate must be exceeded by 
the rate of snow action, else the inequalities of slope would be 
■decreased rather than increased. The accumulated material at 
(A) is, therefore, partly but not chiefly due to denudation of snow- 
free surfaces. It is due chiefly to erosion beneath the snow. Nor 
can it be argnied that the hollows now occupied by snow were 
formed at some past time when ice not snow lay in them. They 
are not ice-made hollows for they are on a steep spur above the 
limits of ice action even in the glacial period. Any past action is, 
therefore, represented here in kind by present action, though there 
would be differences in degree because the heavier snows of the 
past were displaced by the lighter snows of today. 

While it appears that the case presents clear proof of degrada- 
tion by snow it is not so clear how these results were accomplished. 
Beal abrasion on a large scale as in bowlder-shod glaciers is 
ruled out, since glacial striae are wholly absent from nivated sur- 
faces according to both Matthes' observations and my own. Yet 
all nivated surfaces have very distinctive qualities, delicately or- 
ganized slopes which show a marked change from any original 
condition related to water-carving. In the absence of strise, the 
general absence of all but a thin coating of waste even in roch hol- 
lows, and the accumulation of waste up to bowlders in size at the 
lower edge of the nivated zone, I conclude that compacted snow 
or neve of sufficient thickness and gradient may actually pluck 
rock outcrops in the same manner though not at the rate which 
ice exhibits. That the products of nivation may be bowlders as 
well as fine mud would seem clearly to follow increase in effective- 



290 THE ANDES OF SOUTHERN PERU 

ness, due to increase in amount of the accumulated snow; that 
bowlders are actually transported by snow is also shown by their 
presence on the lower margins of nivated tracts. 

Our argument may be made clearer by reference to the ob- 
served action of snow in a particular valley. Snow is shed from 
the higher, steeper slopes to the lower slopes and eventually ac- 
cumulates to a marked degree on the bottoms of the deijressions, 
whence it is avalanched doAvn valley over a series of irregular 
steps on the valley floor. An avalanche takes place through the 
breaking of a section of snow just as an iceberg breaks off the 
end of a tide-water glacier. Evidently there must be pressure 
from behind which crowds the snow forward and precipitates it 
to a lower level. 

As a snow mass falls it not only becomes more consolidated, 
beginning at the plane of impact, but also gives a shock to the 
mass upon which it falls that either starts it in motion or acceler- 
ates its rate of motion. The action must therefore be accom- 
panied by a drag upon the floor and if the rock be close-jointed 
and the blocks, defined by the joint planes, small enough, they will 
be transported. Since snow is not so compact as ice and permits 
included blocks easily to adjust themselves to new resistances, we 
should expect the detached blocks included in the snow to change 
their position constantly and to form irregular scratches, but not 
parallel strise of the sort confidently attributed to stone-shod ice. 

It is to the plasticity of snow that we may look for an ex- 
planation of the smooth-contoured appearance of the landscape in 
the foreground of Fig. 135. The smoothly curved lines are best 
developed where the entire surface was covered with snow, as in 
mid-elevations in the larger snowfields. At higher elevations, 
where the relief is sharper, the snow is shed from the steeper 
declivities and collected in the minor basins and valley heads, 
where its action tends to smooth a floor of limited area, while 
snow-free surfaces retain all their original irregularities of form 
or are actually sharpened. 

The degree of effectiveness of snow and neve action may be 
estimated from the reversed slopes now marked by ponds or small 



GLACIAL FEATURES 291 

marshy tracts scattered throughout the former neve fields, and 
the many niched hollows. They are developed above Pampaconas 
in an admirable manner, though their most perfect and general 
development is in the suromit belt of the Cordillera Vilcapampa 
between Arma and Choquetira, Fig. 135. It is notable in all cases 
where nivation was associated with the work of valley glaciers 
that the rounded nivated slopes break rather sharply with the 
steep slopes that define an inner valley, whose form takes on the 
flat floor and under-cut marginal walls normal to valley glaciation. 

A classification of numerous observations in the Cordillera 
Vilcapampa and in the Maritime Cordillera between Lambrama 
and Antabamba may now be presented as the basis for a tenta- 
tive expression of the law of variation respecting snow motion. 
The statement of the law should be prefaced by the remark that 
thorough checking is required under a wider range of conditions 
before we accept the law as final. Near the lower border of the 
snow where rain and hail and alternate freezing and thawing take 
place, the snow is compacted even though but fifteen to twenty feet 
thick, and appears to have a down-grade movement and to exer- 
cise a slight drag upon its floor when the gradient does not fall 
below 20°. Distinct evidences of nivation were observed on slopes 
with a declivity of 5° near summit areas of past glacial action, 
where the snow did not have an opportunity to be alternately 
frozen and thawed. 

The thickness of the former snow cover could, however, not be 
accurately determined, but was estimated from the topographic 
surroundings to have been at least several hundred feet. Upon 
a 40° slope a snow mass 50 feet thick was observed to be break- 
ing off at a cliff-face along the entire cross-section as if impelled 
forward by thrust, and to be carrying a small amount of waste 
— enough distinctly to discolor the lowermost layers — which was 
shed upon the snowy masses below. With increase in the degree 
of compactness of the snow at successively lower elevations along 
a line of snow discharge, gradients down to 25° were still observed 
to carry strongly crevassed, waste-laden snow down to the melt- 
ing border. It appeared from the clear evidences of vigorous 



292 THE ANDES OF SOUTHERN PERU 

action — the accumulation of waste, the strong crevassing, the 
stream-like character of the discharging snow, and the pro- 
nounced topographic depression in which it lay — that much flatter 
gradients would serve, possibly not more than 15°, for a snow 
mass 150 feet wide, 30 to 40 feet thick, and serving as the out- 
let for a set of tributary slopes about a square mile in area 
and with declivities ranging from small precipices to slopes of 30°. 

We may say, therefore, that the factors affecting the rate of 
motion are (1) thickness, (2) degree of compactness, (3) diurnal 
temperature changes, and (4) gradient. Among these, diurnal 
temperature changes operate indirectly by making the snow more 
compact and also by inducing motion directly. At higher eleva- 
tions above the snowline, temperature changes play a decreas- 
ingly important part. The thickness required varies inversely as 
the gradient, and upon a 20° slope is 20 feet for Avet and compact 
snow subjected to alternate freezing and thawing. For dry snow 
masses above the zone of effective diurnal temperature changes, 
an increasing gradient is required. With a gradient of 40°, less 
than 50 feet of snow will move en masse if moderately compacted 
under its own weight; if further compacted by impact of falling 
masses from above, the required thickness may diminish to 40 
feet and the required declivity to 15°. The gradient may decrease 
to 0° or actually be reversed and motion still continue provided 
the compacting snow approach true neve or even glacier ice as a 
limit. 

From the sharp topographic break between the truly glaciated 
portions of the valley in regions subjected to temporary glacia- 
tion, it is concluded that the eroding power of the moving mass 
is suddenly increased at the point where neve is finally trans- 
formed into true ice. This transformation must be assumed to 
take place suddenly to account for so sudden a change of function 
as the topographic break requires. Below the point at which the 
transformation occurs the motion takes place under a new set of 
conditions whose laws have already been formulated by students 
of glaciologJ^ 

The foregoing readings of gradient and depth of snow are 



GLACIAL FEATURES 



293 



typical of a large number which were made in the Peruvian Andes 
and which have served as the basis of Fig. 195. It will be observed 
that between 15° and 20° there is a marked change of function and 
again between +5° and — 5° declivity, giving a double reversed 
curve. The meaning of the change between 15° and 20° is inferred 
to be that, with gradients over 20°, snow cannot wholly resist 



CURVE OF SNOW MOTION 



300 



250 



ZOO 



150 



100 



50 



-5° 0° 5° 10° 15° 20° 25° 30° 35° 40° 

Fig. 195 — Curve of snow motion. Based on many observations of snow motion to 
show minimum thickness of snow required to move on a given gradient. Figures on 
the left represent thickness of snow in feet. The degrees represent the gradient of the 
surface. The gradients iiave been run in sequence down to 0° for tlie salve of com- 
pleting the acoompanj'ing discussion. Obviously no glacially unmodified valley in a 
region of mountainous relief would start with so low a gradient, though glacial action 
•would soon bring it into existence. Between -)-5° and — 5° the curve is based on the 
gradients of nivated surfaces. 

gravity in the presence of diurnal temperature changes across the 
freezing point and occasional snow or hail storms. "With increase 
of thickness compacting appears to progress so rapidly as to 
permit the transfer of thrust for short distances before absorp- 
tion of thrust takes place in the displaced snow. At 250 feet 
thorough compacting appears to take place, enabling the snow to 
move out under its own weight on even the faintest slopes ; while, 



\ • 

m ^^^.^^^ 

* 



29J< THE ANDES OF SOUTHERN PERU 

with a thickness still greater, the resulting neve may actually be 
forced up slight inclines whose declivity appears to approach 5" 
as a limit. I have nowhere been able to find in truly nivated areas 
reversed curves exceeding 5°, though it should be added that de- 
pressions whose leeward slopes were reversed to 2° and 3° are 
fairly common. If the curve were continued we should undoubt- 
edly find it again turning to the left at the point where the thick- 
ness of the snow results in the transformation of snow to ice. 
From the sharp topographic break observed to occur in a narrow 
belt between the neve and the ice, it is inferred that the erosive 
power of the neve is to that of the ice as 2:4 or 1:5 for equal 
areas; and that reversed slopes of a declivity of 10° to 15° may 
be formed by glaciers is well known. Precisely what thickness of 
snow or neve is necessary and what physical conditions effect its 
transformation into ice are problems not included in the main 
theme of this chapter. 

It is important that the proposed curve of snow motion under 
minimum conditions be tested under a large variety of circum- 
stances. It may possibly be found that each climatic region re- 
quires its special modifications. In tropical mountains the sud- 
den alternations of freezing and thawing may effect such a high 
degree of compactness in the snow that lower minimum gradients 
are required than in the case of mid-latitude mountains where 
the perpetual snow of the high and cold situations is compacted 
through its own weight. Observations of the character introduced 
here are still unattainable, however. It is hoped that they will 
rapidly increase as their significance becomes apparent; and that 
they have high significance the striking nature of the curve of 
motion seems clearly to establish. 

BEEGSCHRUNDS AND CIRQUES 

The facts brought out by the curve of snow-motion (Fig. 195) 
have an immediate bearing on the development of cirques, whose 
precise mode of origin and development have long been in doubt. 
Without reviewing the arguments upon which the various hy- 
potheses rest, we shall begin at once with the strongest explana- 



GLACIAL FEATURES 295 

tion — W. D. Johnson's famous bergschrund hypothesis. The 
critical condition of this hypothesis is the diurnal migration 
across the freezing point of the air temperature at the bottom of 
the schrund. Alternate freezing and thawing of the water in the 
joints of the rock to which the schrund leads, exercise a quarry- 
ing effect upon the rock and, since this effect is assumed to take 
place at the foot of the cirque, the result is a steady retreat of 
the steep cirque wall through basal sapping. 

While Johnson's hypothesis has gained wide acceptance and 
is by many regarded as the final solution of the cirque problem 
it has several weaknesses in its present form. In fact, I believe 
it is but one of two factors of equal importance. In the first 
place, as A. C. Andrews " has pointed out, it is extremely improb- 
able that the bei"gschrund of glacial times under the conditions of 
a greater volume of snow could have penetrated to bedrock at the 
base of the cirque where the present change of slope takes place. 
In the second place, the assumption is untenable that the berg- 
schrund in all cases reaches to or anywhere near the foot of the 
cirque Avail. A third condition outside the hypothesis and con- 
tradictory to it is the absence of a bergschrund in snowfields at 
many valleys heads where cirques are well developed! 

Johnson himself called attention to the slender basis of ob- 
servation upon which his conclusions rest. In spite of his own 
caution with respect to the use of his meager data, his hypothesis 
has been applied in an entirely too confident manner to all kinds 
of cirques under all kinds of conditions. Though Johnson de- 
scended an open bergschrund to a rock floor upon which ice rested, 
his observations raise a number of proper questions as to the 
application of these valuable data: How long are bergschrunds 
open? How often are they open? Do they everywhere open to 
the foot of the cirque wall? Are they present for even a part of 
the year in all well-developed cirques? Let us suppose that it 
is possible to find many cirques filled with snow, not ice, sur- 
rounded by truly precipitous walls and with an absence of berg- 

' Corrosion of Gravity Streams \vitli Application of the loe Flood Hypothesis, 
Journ. and Proc. of the Eoyal Society of N. S. Wales, Vol. 43, 1909, p. 286. 



296 



THE ANDES OF SOUTHERN PERU 




schrunds, how shall we explain the topographic depressions ex- 
cavated underneath the snow"? If cirque formation can be shown 
to take place without concentrated frost action at the foot of the 
bergschrund, then is the bergschrund not a secondary rather than 
a primary factor? And must we not further conclude that when 
present it but hastens an action which is common to all snow-cov- 
ered recesses? 

It is a pleasure to say that we may soon have a restatement of 
the cirque problem from the father of the bergschrund idea. The 
argument in this chapter was presented orally 
to him after he had remarked that he was glad 
to know that some one was finding fault Avith his 
hypothesis. "For," he said, with admirable 
spirit, " I am about to make a most violent 
attack upon the so-called Johnson hypothesis." 
I wish to say frankly that while he regards 
the following argument as a valid addition to 
the problem, he does not think that it solves 
the problem. There are many of us who will 
read his new explanation with the deepest 
interest. 

"We shall begin with the familiar fact that many valleys, now 
without perpetual snow, formerly contained glaciers from 500 to 
1,000 feet thick and that their snowfields were of wide extent and 
great depth. At the head of a given valley where the snow is 
crowded into a small cross-section it is compacted and suffers a re- 
duction in its volume. At first nine times the volume of ice, the 
gradually compacting neve approaches the volume of ice as a limit. 
At the foot of the cirque wall we may fairly assume in the absence 
of direct observations, a volume reduction of one-half due to com- 
pacting. But this is offset in the case of a well-developed cirque 
by volume increases due to the convergence of the snow from the 
surrounding slopes, as shown in Fig. 196. Taking a tjq)ical 
cirque from a point above Vilcabamba pueblo I find that the 
radius of the trough's end is to the radius of the upper wall 
of the cirque as 1:4; and since the corresponding surfaces are 



FiQ. 196— Rela- 
tion of cirque wall to 
trough's end at the 
head of a glaciated 
valley. The ratio 
of the inner to the 
outer radius is 1:4. 



GLACIAL FEATURES 



297 



to one another as the squares of their similar dimensions we 
have 1:4 or 1 : 16 as the ratio of their snow areas. If no com- 
pacting took place, then to accommodate all the snow in the glacial 
trough would require an increase in thickness in the ratio of 
1:4. If the snow were compacted to half its original volume then 
the ratio would be 1:2. Now, since the volume ratio of ice to 




Fig. 197 — ^Mode of cirque formation. Taking the facts of snow depth represented 
in the curve, Fig. 195, and transposing them over a profile (the heavy line) which 
ranges from 0° declivity to 50°, we find that the greatest excess of snow occurs 
roughly in the center. Here ice will first form, at the bottom of the snow in the 
advancing hemicycle of glaciation, and here it will linger longest in the hemioycle 
of retreat. Here also there will be the greatest mass of nfivS. All of these factors 
are self-stimulating and will increase in time until the floor of the cirque is flattened 
or depressed sufficiently to offset through uphill iee-floAV the augmented forces of 
erosion. The effects of self-stimulation are shown by "snow increase"; the ice shoe 
at the bottom of the cirque is expressed by " ice factor." The form accompanying both 
these terms is merely suggestive. The top of " excess snow " has a gradient char- 
acteristic of the surface of snow fields. A preglacial gradient of 0° is not permissible, 
but I have introduced it to complete the discussion in the text and to illustrate the 
flat floor of a cirque. A bergschrund is not required for any stage of this process, 
though the process is hastened wherever bergschrunds exist. 

snow is 1 : 9 and the thickness of the ice down valley is, say 400 
feet, the equivalent of loose snow at the foot of the cirque must 
be more than 1 : 4 over 1 : 9 or more than two and one-quarter 
times thicker, or 400 feet thick; and would give a pressure of 
(900 -^ 10) X 62.5 pounds, or 5,625 pounds, or a little less than 
three tons per square foot. Since a pressure of 2,500 pounds per 
square foot will convert snow into ice at freezing temperature, it 



298 THE ANDES OF SOUTHERN PERU 

is clear that ice and not snow was the state at the bottom of the 
mass in glacial times. Furthei", between the surface of the snow 
and the surface of the bottom layer of the ice there must have 
been every gradation between loose snow and firm ice, with the 
result that a thickness much less than 900 feet must be assumed. 
Precisely what thickness would be found at the foot of the cirque 
wall is unknown. But granting a thickness of 400 feet of ice an 
additional 300 feet for neve and snow would raise the total to 700 
feet. 

The application of the facts in the above paragraph is clearly 
seen when we refer to Fig. 197. The curve of snow motion of Fig. 
195 is applied to an unglaciated mountain valley. Taking a 
normal snow surface and filling the valley head it is seen that 
the excess of snow depth over the amount required to give motion 
is a measure at various points in the valley head and at different 
gradients of the erosive force of the snoAV. It is strikingly con- 
centrated on the 15°-20° gradient which is precisely where the so- 
called process of basal sapping is most marked. If long continued 
the process will lead to the developing of a typical cirque for it is 
a process that is self-stimulating. The more the valley is changed 
in form the more it tends to change stUl further in form because 
of deepening snowfields until clitfed pinnacles and matterhorns 
result. 

By further reference to the figure it is clear that a schrund 
350 feet deep could not exist on a cirque wall •ni.th a declivity of 
even 20° without being closed by flow, unless we grant more rapid 
flow helow the crevasse. In the case of a glacier flowing over a 
nearly flat bed away from the cirque it is difficult to conceive of a 
rate of flow greater than that of snow and neve on the steep lower 
portion of the cirque wall, when movement on that gradient begins 
Avith snow but 20 feet thick. 

In contrast to this is the view that the schrund line should lie 
well up the cirque wall where the snow is comparatively thin and 
where there is an approach to the lower limits of movement. 
The schrund would appear to open where the bottom material 
changes its form, i.e., where it first has its motion accelerated by 



GLACIAL FEATURES 299 

transformation into neve. In this view the schrund opens not at 
the foot of the cirque wall but well above it as in Fig. 198, in 
which C represents snow from top to bottom; B, neve; and A, ice. 
The required conditions are then (1) that the steepening of the 
cirque wall from x to y should be effected by sapping originated 
at y through the agencies outlined by Johnson; (2) that the steep- 
ening from X to y should be effected by sapping originated at x 
through the change of the agent from neve to ice with a sudden 
change of function; (3) and that the essential unity of the wall 
x-y-s be maintained through the erosive power of the neve, which 
would tend to offset the formation of a shelf along a horizontal 
plane passed through y. The last-named process not only appears 
entirely reasonable from the conditions of gradient and depth out- 
lined on pp. 296 to 298, but also meets the actual field conditions in 
all the cases examined in the Peruvian Andes. This brings up 
the second and third of our main considerations, that the berg- 
schrund does not always or even in many cases reach the foot of 
the cirque wall, and that cirques exist in many cases where berg- 
schrunds are totally absent. 

It is a striking fact that frost action at the bottom of the 
bergschrund has been assumed to be the only effective sapping 
force, in spite of the common observation that bergschrunds lie 
in general well toward the upper limits of snowfields — so far, in 
fact, that their bottoms in general occur several hundred feet 
above the cirque floors. Is the cirque under these circumstances 
a result of the schrund or is the schrund a result of the cirque? 
In ivhat class of cirques do schrunds develop? If cirque develop- 
ment in its early stages is not marked by the development of 
bergschrunds, then are bergschrunds an essential feature of 
cirques in their later stages, however much the sapping process 
may be hastened by schrund formation? 

Our questions are answered at once by the indisputable facts 
that many schrunds occur well toward the upper limit of snow, 
and that many cirques exist whose snowfields are not at all broken 
by schrunds. It was with great surprise that I first noted the 
bergschrunds of the Central Andes, especially after becoming 



300 



THE ANDES OF SOUTHERN PERU 



familiar witli Jolinson's apparently coraplete proof of their 
genetic relation to the cirques. But it was less surprising to dis- 
cover the position of the few observed — ^high up on the cirque 
walls and always near the upper limit of the sno^vfields. 

A third fact from regions once glaciated but now suow-free 
also combined with the two preceding facts in weakening the whole- 
sale application of Johnson's hypothesis. In many headwater 
basins the cirque whose wall at a distance seemed a unit was really 
broken into two unequal portions; a lower, much grooved and 
rounded portion and an u^Dper unglaciated, steep-walled portion. 
This condition was most puzzling in view of the accepted explana- 
tion of cirque formation, and it Avas not until the two first-named 
facts and the applications of the curves of snow motion were 
noted that the meaning of the break on the cirque became clear. 

Eeferring to Fig. 198 we see at 
once that the break occurs at y 
and means that under favorable 
topographic and geologic condi- 
tions sajDping at y takes place 
faster than at x and that the re- 
treat of y-z is faster than x-y. 
It mil be clear that when these 
conditions are reversed or sapping at x and at y are equal a 
single wall will result. On reference to the literature I find that 
Gilbert recently noted this feature and called it the schrundline.' 
He believes that it marks the base of the bergschrund at a late 
stage in the excavation of the cirque hasin. He notes further that 
the lower less-steep slope is glacially scoured and that it forms 
"a sort of shoulder or terrace." 

If all the structural and topographic conditions were known in 
a great variety of gathering basins we should undoubtedly find 
in them, and not in special forms of ice erosion, an explanation 
of the various forms assumed by cirques. The limitations in- 
herent in a high-altitude field and a limited snow cover prevented 




Fig. 19S — The development of cirques. 
See text, p. 299, and Fig. 199. 



" G. K. Gilbert, Systematic Asymmetry of Crest Lines in the High Sierra of 
California. Jour. Geol., Vol. 12, 1904, p. 582. 



GLACIAL FEATURES 301 

me from solving the problem, but it offered suificient evidence at 
least to indicate the probable lines of approach to a solution. For 
example it is noteworthy that in all the cases examined the 
schrundline was better developed the further glacial erosion had 
advanced. So constantly did this generalization check up, that if 
at a distance a short valley was observed to end in a cirque, I 
knew at once and long before I came to the valley head that a 
shoulder below the schrundline did not exist. At the time this 
observation was made its significance was a mystery, but it repre- 
sents a condition so constant that it forms one of the striking 
features of the glacial forms in the headwater region. 

The meaning of this feature is represented in Fig. 199, in 
which three successive stages in cirque development are shown. 
In A, as displayed in small val- 
leys or mountainside alcoves 
which were but temporarily oc- 
cupied by snow and ice, or as in 
all higher valleys during the 
earlier stages of the advancing p,^_ 199-Further stages in the de- 

hemicycle of glaciation, snow velopment of cirques. See p. 299 and Fig. 

collects, a short glacier forms, 

and a bergschrund develops. As a result of the concentrated frost 
action at the base of the bergschrund a rapid deepening and steep- 
ening takes place at a. As long as the depth of snow (or snow and 
neve) is slight the bergschrund may remain open. But its existence 
at this particular point is endangered as the cirque grows, since the 
increasing steepness of the slope results in more rapid snow move- 
ment. Greater depth of snow goes hand in hand with increasing 
steepness and thus favors the formation of neve and even ice at 
the bottom of the moving mass and a constantly accelerated rate 
of motion. At the same time the bergschrund should appear 
higher up for an independent reason, namely, that it tends to 
form between a mass of slight movement and one of greater 
movement, which change of function, as already pointed out, 
would appear to be controlled by change from snow to neve or 
ice on the part of the bottom material. 



302 THE ANDES OF SOUTHERN PERU 

The first stages in the upward migration of the bergschrund 
will not effect a marked change from the original profile, since 
the converging slopes, the great thickness of neve and ice at this 
point, and the steep gradient all favor powerful erosion. "When, 
however, stage C is reached, and the bergschrund has retreated 
to c", a broader terrace results below the sehrundline, the gradient 
is decreased, the ice and neve (since they represent a constant dis- 
charge) are spread over a greater area, hence are thinner, and we 
have the cirque taking on a compound character with a lower, less 
steep and an upper, precipitous section. 

It is clear that a closely jointed and fragile rock might be 
quarried by moving ice at c'-c" and the cirque wall extended un- 
broken to x; it is equally clear that a homogeneous, unjoiuted gran- 
ite would offer no opportunities for glacial plucking and would 
powerfully resist the much slower process of abrasion. Thus 
Gilbert " observed the sehrundline in the granites of the Sierra 
Nevada, which are "in large part structureless" and my own ob- 
servations show the sehrundline well developed in the open- 
jointed granites of the Cordillera Vilcapampa and wholly absent 
in the volcanoes of the Maritime Cordillera, where ashes and cin- 
ders, the late products of volcanic action, form the easily eroded 
walls of the steep cones. Somewhere between these extremes — 
lack of a variety of observations prevents our saying wh^re — the 
resistance and the internal structure of the rock will just permit 
a cirque wall to extend from x to c' " of Fig. 199. 

A common feature of cirques that finds an explanation in the 
proposed hypothesis is the notch that commonly occurs at some 
point where a convergence of slopes above the main cirque wall 
concentrates snow discharge. It is proposed to call this type the 
notched cirque. It is highly significant that these notches are 
commonly marked by even steeper descents at the point of dis- 
charge into the main cirque than the remaining portion of the 
cirque wall, even when the discharge was from a very small 
basin and in the form of snow or at the most neve. The excess of 
discharge at a point on the basin rim ought to produce the form 

'° Op. cit., p. 300; reference on p. 582. 



GLACIAL FEATURES 303 

we find there under the conditions of snow motion outlined in 
earlier paragraphs. It is also noteworthy that it is at such a 
point of concentrated discharge that crevasses no sooner open than 
they are closed by the advancing snow masses. To my mind the 
whole action is eminently representative of the action taking 
place elsewhere along the cirque wall on a smaller scale. 

"What seems a good test of the explanation of cirques here 
proposed was made in those localities in the Maritime Cordillera, 
where large snowbanks but not glaciers affect the form of the 
catchment basins. A typical case is shown in Fig. 201. As in 
many other cases we have here a great lava plateau broken fre- 
quently by volcanic cones of variable composition. Some are of 
lava, others consist of ashes, still others of tuff and lava and 
ashes. At lower elevations on the east, as at 16,000 feet between 
Antabamba and Huancarama, evidences of long and powerful 
glaciers are both numerous and convincing. But as we rise still 
higher the glaciated topography is buried progressively deeper 
under the varying products of volcanic action, until finally at the 
summit of the lava fields all evidences of glaciation disappear in 
the greater part of the country between Huancarama and the 
main divide. Nevertheless, the summit forms are in many cases 
as significantly altered as if they had been molded by ice. Pre- 
cipitous cirque walls surround a snow-filled amphitheater, and 
the process of deepening goes forward under one's eyes. No 
moraines block the basin outlets, no U-shaped valleys lead for- 
ward from them. We have here to do with post-glacial action 
pure and simple, the volcanoes having been formed since the close 
of the Pleistocene. 

Likewise in the pass on the main divide, the perpetual snow 
has begun the recessing of the very recent volcanoes bordering 
the pass. The products of snow action, muds and sands up to very 
coarse gravel, glaciated in texture with an intermingling of 
blocks up to six inches in diameter in the steeper places, are col- 
lected into considerable masses at the snowline, where they form 
broad sheets of waste so boggy as to be impassable except by care- 
fully selected routes. No ice action whatever is visible below 



304 THE ANDES OF SOUTHERN PERU 

the snowline and the snow itself, though wet and compact, is not 
underlain by ice. Yet the process of hollowing goes forward 
visibly and in time will produce serrate forms. In neither case 
is there the faintest sign of a bergschrund; the gradients seem 
so well adjusted to the thickness and rate of movement of the 
snow from point to point that the marginal crack found in many 
snowfields is absent. 

The absence of bergschrunds is also noteworthy in many locali- 
ties where formerly glaciation took place. This is notoriously the 
case in the summit zone of the Cordillera Vilcapampa, where the 
accumulating snows of the steep cirque walls tumble down hun- 
dreds of feet to gather into prodigious snowbanks or to form 
neve fields or glaciers. From the converging walls the snowfalls 
keep up an intermittent bombardment of the lower central snow 
masses. It is safe to say that if by magic a bergschrund could 
be opened on the instant, it would be closed almost immediately 
by the impetus supplied by the falling snow masses. The explana- 
tion appears to be that the thicker snow and neve concentrated at 
the bottom of the cirque results in a corresponding concentration 
of action and effect; and cirque development goes on without 
reference to a bergschrund. The chief attraction of the berg- 
schrund hypothesis lies in the concentration of action at the foot 
of the cirque wall. But in the thickening of the snow far beyond 
the minimum thickness required for motion at the base of the 
cirque wall and its change of function with transformation into 
neve, we need invoke no other agent. If a bergschrund forms, its 
action may take place at the foot of the cirque wall or high up on 
the wall, and yet sapping at the foot of the wall continue. 

From which we conclude (1) that where frost action occurs at 
the bottom of a bergschrund opening to the foot of the cirque wall 
it aids in the retreat of the wall; (2) that a sapping action takes 
place at this point whether or not a bergschrund exists and that 
bergschrund action is not a necessary part of cirque formation; 
(3) that when a more or less persistent bergschrund opens on the 
cirque wall above its foot it tends to develop a schrundline with 
a marked terrace below it; (4) that schrundlines are best devel- 



72'40' 



,13' 20' 



72'40' 



ENO.AND PTG.BYTHE TOPOGRAPHIC ENGRAVING CO. WASH.,n. C. 



I3'S0' 



Edition of 19IS. 



THE YALE EERirVXAST EXPEDITION OF 1911 

HIRAM BINGHAM. DIRECTOR 

I.AMBILAMA. OUADEAK&I.E 




CoQtouT m(oi'VTil200 fout. 



GLACIAL FEATURES 305 

oped in the mature stages of topographic development in the gla- 
cial cycle; (5) that the varying rates of snow, neve, and ice motion 
at a valley head are the persistent features to which we must look 
for topographic variations; (6) that the hypothesis here pro- 
posed is applicable to all cases whether they involve the presence 
of snow or neve or ice or any combination of these, and whether 
bergschrunds are present or not; and (7) at the same time affords 
a reasonable explanation for such variations in forms as the com- 
pound cirque with its schrundline and terrace, the unbroken cirque 
wall, the notched cirque, and the recessed, snow-covered mountain 
slopes unaffected by ice. 

ASYMMETBICAL CREST LINES AND ABNORMAL VALLEY PROFILES IN THE 

CENTRAL ANDES 

To prove that under similar conditions glacial erosion may be 
greater than subaerial denudation quantitative terms must be 
sought. Only these will carry conviction to the minds of many 
opponents of the theory that ice is a vigorous agent of erosion. 
Gilbert first showed in the Sierra Nevada that headwater glaciers 
eroded more rapidly than nonglaeial agents under comparable 
topographic and structural conditions." Oddly enough none of 
the supporters of opposing theories have replied to his argu- 
ments; instead they have sought evidence from other regions to 
show that ice cannot erode rock to an important degree. In this 
chapter evidence from the Central Andes, obtained in 1907 and 
1911, will be given to show the correctness of Gilbert's proposition. 

The data Avill be more easily understood if Gilbert's argument 
is first outlined. On the lower slopes of the glaciated Sierra 
Nevada asymmetry of form resulted from the presence of ice on 
one side of each ridge and its absence on the other (Fig. 200). 
The glaciers of these lower ridges were the feeblest in the entire 
region and were formed on slopes of small extent ; they were also 
short-lived, since they could have existed only when glacial con- 
ditions had reached a maximum. Let the broken line in the upper 

"Op. cit., p. 300; see pp. 579-588 and Fig. 8. 



306 THE ANDES OF SOUTHERN PERU 

part of the figure represent the preglacial surface and the solid 
line beneath it the present surface. It will not matter what value 
we give the space between the two lines on the left to express non- 
glacial erosion, since had there been no glaciers it would be the 
same on both sides of the ridge. The feeble glacier occupying the 
right-hand slope was able in a very brief period to erode a de- 
pression far deeper than the normal agents of denudation were 
able to erode in a much longer period, i.e., during all of intergla- 
cial and postglacial time. Gilbert concludes: "The visible ice- 
made hollows, therefore, represent the local excess of glacial over 
nonglacial conditions . ' ' 

In the Central Andes are many volcanic peaks and ridges 
formed since the last glacial epoch and upon them a remarkable 



SorSW NorNE s N 

Fig. 200 — Diagrammatic cross-section Fig. 201 — Postglaciixl volcano recessed 

of a riJge glaciated on one side only; on shady southern side by the process of 
with hypothetical proiile (broken line) nivation. Absolute elevation 18,000 feet 
of preglacial surface. (5,490 m.), latitude 14° S., JIaritime 

Cordillera, Peru. 

asymmetry has been developed. Looking southward one may see 
a smoothly curved, snow-free, northward-facing slope rising to a 
crest line which appears as regular as the slope leading to it. 
Looking northward one may see by contrast (Fig. 194) sharp 
ridges, whose lower crests are serrate, separated by deeply re- 
cessed, snow-filled mountain hollows. Below this highly dissected 
zone the slopes are smooth. The smooth slope represents the 
work of water ; the irregular slopes are the work of snow and ice. 
The relation of the north and south slopes is diagrammaticaUy 
shown in Fig. 201. 

To demonstrate the erosive effects of snow and ice it must be 
shown: (1) that the initial slopes of the volcanoes are of post- 
glacial age; (2) that the asymmetry is not structural; (3) that the 
snow-free slopes have not had special protection, as through a 
more abundant plant cover, more favorable soil texture, or other- 
wise. 



I 



GLACIAL FEATURES 307 

Proof of the postglacial origin of the volcanoes studied in this 
connection is afforded: (1) by the relation of the flows and the 
ash and cinder beds about the bases of the cones to the glacial 
topography; (2) by the complete absence of glacial phenomena be- 
low the present snowline. Ascending a marginal valley (Fig. 202), 
one comes to its head, where two tributaries, with hanging rela- 
tions to the main valley, come down from a maze of lesser valleys 
and irregular slopes. Glacial features of a familiar sort are every- 
where in evidence until we come to the valley heads. Cirques, re- 
versed grades, lakes, and striae are on every hand. But at alti- 
tudes above 17,200 feet, recent volcanic deposits have over large 
areas entirely obscured the older glacial topography. The glacier 
which occupied the valley of Fig. 202 was more than one-quarter 
of a mile wide, the visible portion of its valley is now over six 
miles long, but the extreme head of its left-hand tributary is so 
concealed by volcanic material that the original length of the gla- 
cier cannot be determined. It was at least ten miles long. From 
this point southward to the border of the Maritime Cordillera no 
evidence of past glaciation was observed, save at Solimana and 
Coropuna, where slight changes in the positions of the glaciers 
have resulted in the development of terminal moraines a little be- 
low the present limits of the ice. 

From the wide distribution of glacial features along the north- 
eastern border of the Maritime Cordillera and the general absence 
of such features in the higher country farther south, it is con- 
cluded that the last stages of volcanic activity were completed in 
postglacial time. It is equally certain, however, that the earlier 
and greater part of the volcanic material was ejected before 
glaciation set in, as shown by the great depth of the canyons (over 
5,000 feet) cut into the lava flows, as contrasted mth the rela- 
tively slight filling of coarse material which was accumulated on 
their floors in the glacial period and is now in process of dissec- 
tion. Physiographic studies throughout the Central Andes demon- 
strate both the general distribution of this fill and its glacial 
origin. 

So recent are some of the smaller peaks set upon the lava 



308 THE ANDES OF SOUTHERN PERU 

plateau that forms the greater part of the Maritime Cordillera, 
that the snows massed on their shadier slopes have not yet ef- 
fected any important topographic changes. The symmetrical 
peaks of this class are in a few cases so very recent that they are 
entirely nneroded. Lava flows and beds of tuff appear to have 
originated but yesterday, and shallow lava-dammed lakes retain 
their original shore relations. In a few places an older topog- 
raphy, glacially modified, may still be seen showing through a 
veneer of recent ash and cinder deposits, clear evidence that the 
loftier parts of the lava plateau were glaciated before the last 
volcanic eruption. 

The asymmetry of the peaks and ridges in the Maritime Cordil- 
lera cannot be ascribed to the manner of eruption, since the con- 
trast in declivity and form is persistently between northern and 
southern slopes. Strong and persistent winds from a given direc- 
tion undoubtedly influence the form of volcanoes to at least a 
perceptible degree. In the case in hand the ejectamenta are 
ashes, cinders, and the like, which are blown into the air and have 
at least a small component of motion down the ^\T.nd during both 
their ascent and descent. The prevailing winds of the high 
plateaus are, however, easterly and the strongest winds are from 
the west and blow daily, generally in the late afternoon. Both 
wind directions are at right angles to the line of asymmetry, and 
we must, therefore, rule out the winds as a factor in effecting the 
slope contrasts which these mountains display. 

It remains to be seen what influence a covering of vegetation 
on the northern slopes might have in protecting them from ero- 
sion. The northern slopes in this latitude (14° S.) receive a 
much greater quantity of heat than the southern slopes. Above 
18,000 feet (5,490 m.) snow occurs on the shady southern sloj^es, 
but is at least a thousand feet higher on the northern slopes. It 
is therefore absent from the northern side of all but the highest 
peaks. Thus vegetation on the northern slopes is not limited by 
snow. Bunch grass — the characteristic ichu of the mountain 
shepherds — scattered spears of smaller grasses, large ground 
mosses called yareta, and lichens extend to the snowline. This 



GLACIAL FEATURES 309 

vegetation, however, is so scattered and thin above 17,500 feet 
(5,330 m.) that it exercises no retarding influence on the run-off. 
Far more important is the porous nature of the volcanic material, 
which allows the rainfall to be absorbed rapidly and to appear in 
springs on the lower slopes, where sheets of lava direct it to the 
surface. 

The asymmetry of the north and south slopes is not, then, the 
result of preglacial erosion, of structural conditions, or of special 
protection of the northern slopes from erosion. It must be con- 
cluded, therefore, that it is due to the only remaining factor — 
snow distribution. The southern slopes are snow-clad, the north- 
ern are snow-free — in harmony with the line of asymmetry. The 
distribution of the snow is due to the contrasts between shade and 
sun temperatures, which find their best expression in high alti- 
tudes and on single peaks of small extent. Frankland's observa- 
tions with a black-bulb thermometer in vacuo show an increase in 
shade and sun temperatures contrasts of over 40° between sea 
level and an elevation of 10,000 feet. VioUe's experiments show 
an increase of 26 per cent in the intensity of solar radiation be- 
tween 200 feet and 16,000 feet elevation. Many other observa- 
tions up to 16,000 feet show a rapid increase in the difference be- 
tween sun and shade temperatures with increasing elevation. In 
the region herein described where the snowline is between 18,000 
and 19,000 feet (5,490 to 5,790 m.) these contrasts are still further 
heightened, especially since the semi-arid climate and the conse- 
quent long duration of sunshine and low relative humidity afford 
the fullest play to the contrasting forces. The coefficient of ab- 
sorption of radiant energy by water vapor is 1,900 times that of 
air, hence the lower the humidity the more the radiant energy 
expended upon the exposed surface and the greater the sun and 
shade contrasts. The effect of these temperature contrasts is 
seen in a canting of the snowline on individual volcanoes amount- 
ing to 1,500 feet in extreme instances. The average may be placed 
at 1,000 feet. 

The minimum conditions of snow motion and the bearing of 
the conclusions upon the formation of cirques have been described 



310 THE ANDES OF SOUTHERN PERU 

in the chapters immediately preceding. It is concluded that suow 
moves upon 20° slopes if the snow is at least forty feet deep, 
and that through its motion under more favorable conditions of 
greater depth and gradient and the indirect effects of border 
melting there is developed a hollow occupied by the snow. Actual 
ice is not considered to be a necessary condition of either move- 
ment or erosion. We may at once accept the conclusion that the 
invariable association of the cirques and steepened profiles with 
snoAvfields proves that snow is the predominant modifying agent. 

An argument for glacial erosion based on profiles and steep 
cirque walls in a volcanic region has peculiar appropriateness in 
view of the well-known symmetrical form of the typical volcano. 
Instead of varied forms in a region of complex structure long 
eroded before the appearance of the ice, we have here simple 
forms which immediately after their development were occupied 
by snow. Ever since their completion these cones have been 
eroded by snow on one side and by ivater on the other. If snow 
cannot move and if it protects the surface it covers, then this sur- 
face should be uneroded. All such surfaces should stand higher 
than the slopes on the opposite aspect eroded by water. But these 
assumptions are contrary to fact. The slopes underneath the 
snow are deeply recessed; so deeply eroded indeed, that they are 
bordered by steep cliffs or cirque walls. The products of erosion 
also are to some extent displayed about the border of the snow 
cover. In strong contrast the snow-free slopes are so slightly 
modified that little of their original symmetry is lost — only a few 
low hills and shallow valleys have been formed. 

The measure of the excess of snow erosion over water erosion 
is therefore the difference between a northern or water-formed 
and a southern or snow-formed profile, Fig. 200. This difference 
is also shown in Fig. 201 and from it and the restored initial pro- 
files we conclude that the rate of water erosion is to that of niva- 
tion as 1:3. This ratio has been derived from numerous obser- 
vations on cones so recently formed that the interfluves without 
question are still intact. 

Thus far only those volcanoes have been considered which 



GLACIAL FEATURES 



311 



have been modified by nivation. There are, however, many vol- 
canoes which have been eroded by ice as well as by snow and 
water. It will be seen at once that where a great area of snow is 
tributary to a single valley, the snow becomes compacted into 
neve and ice, and that it then erodes at a much faster rate. Also 
a new force — ^plucking — ^is 
called into action when ice is 
present, and this greatly ac- 
celerates the rate of erosion. 
While it lies outside the 

limits of my subject to de- j-,^_ 202-Graphic representation 




termine quantitatively the" 
ratio between water and ice 
action, it is worth pointing 
out that by this method a 
ratio much in excess of 1 : 3 
is determined, which even in 
this rough form is of con- 
siderable interest in view of 
the arguments based on the 
protecting influence of both 
ice and snow. I have, in- 
deed, avoided the question 
of ice erosion up to this 
point and limited myself to 
those volcanoes which have 
been modified by nivation only, since the result is more striking 
in view of the aU. but general absence of data relating to this form 
of erosion. 

If we now turn to the valley profiles of the glaciated portions 
of the Peruvian Andes, we shall see the excess of ice over water 
erosion expressed in a manner equally convincing. To a thought- 
ful person it is one of the most remarkable features of any gla- 
ciated region that the flattest profiles, the marshiest valley flats, 
and the most strongly meandering stretches of the streams should 
occur near the heads of the valleys. The mountain shepherds 



amount of glacial erosion during the glacial 
period. In the background are mature slopes 
surmounted by recessed asymmetrical peaks. 
The river entrenched itself below the mature 
slopes before it began to aggrade, and, when ag- 
gradation set in, had cut its valley floor to 
a'-b'-c. By aggradation the valley floor was 
raised to a-b while ice occupied the valley head. 
By degradation the river has again barely 
lowered its channel to a'-b', the ice has disap- 
peared, and the depression of the profile repre- 
sents the amount of glacial erosion. 

a'-b'-c := preglacial profile. 

a-b-d-c = present profile. 

b'-d-c-b = total ice erosion in the glacial 
period. 

a-b = surface of an alluvial valley fill 
due to excessive erosion at valley 
head. 

b-b' = terminal moraine. 

d-c = cirque wall. 

e, e' e" = asymmetrical summits. 



312 



THE ANDES OF SOUTHERN PERU 




recognize this condition and 
drive their flocks up from 
the wanner valley into the 
mountain recesses, confi- 
dent that both distance 
and elevation will be off- 
set by the extensive pas- 
tures of the finest ichu 
grass. Indeed, to be near 
the grazing grounds of 
sheep and llamas which are 
their principal means of 
subsistence, the Indians 
have built their huts at the 
extraordinarily lofty eleva- 
tions of 16,000 to 17,000 feet. 

An examination of a 
large number of these val- 
leys and the plotting of 
their gradients discloses 
the striking fact that the 
heads of the valleys were 
deeply sunk into the moun- 
tains. It is thus possible 
by restoring the preglacial 
profiles to measure with 
considerable certainty the 
excess of ice over water 
erosion. 

The results are graphi- 
cally expressed in Fig. 202. 
It will be seen that until 
glacial conditions inter- 
vened the stream was flow- 
ing on a rock floor. During 
the whole of glacial time it 



GLACIAL FEATURES 313 

was aggrading its rock floor below b' and forming a deep valley 
fill. A return to warmer and drier conditions led to the dis- 
section of the fill and this is now in progress. The stream has 
not yet reached its preglacial profile, but it has almost reached it. 
We may, therefore, say that the preglacial valley profile below b' 
fixes the position of the present profile just as surely as if the 
stream had been magically halted in its work at the beginning of the 
period of glaciation. There, b'-d-c-b represents the amount of ice 
erosion. To be sure the line b-c is inference, but it is reasonable in- 
ference and, whatever position is assigned to it, it cannot be coin- 
cident with b'-d, nor can it be anywhere near it. The break in the 
valley profile at b' is always marked by a terminal moraine, re- 
gardless of the character of the rock. This is not an accidental 
but a causal association. It proves the power of the ice to erode. 
In glacial times it eroded the quantity h-c-d-V. This is not an 
excess of ice over water erosion, but an absolute measure of ice 
erosion, since a'-b' has remained intact. The only possible error 
arises from the position assigned b-c, and even if we lower it to 
b-G (for which we have no warrant but extreme conservatism) we 
shall still have left b'-c'-d-b as a striking value for rock erosion 
(plucking and abrasion) by a valley glacier. 

A larger diagram, Fig. 203, represents in fuller detail the 
topographic history of the Andes of southern Peru and the rela- 
tive importance of glaciation. The broad spurs with grass- 
covered tops that end in steep scarps are in wonderful contrast to 
the serrate profiles and truncated spurs that lie within the zone 
of past glaciation. In the one case we have minute irregularities 
on a canyon wall of great dimensions; in the other, more even 
walls that define a glacial trough with a flat floor. Before glacia- 
tion on a larger scale had set in the right-hand section of the dia- 
gram had a greater relief. It was a residual portion of the moun- 
tain and therefore had greater height also. Glaciers formed upon 
it in the Ice Age and glaciation intensified the contrast between 
it and the left-hand section ; not so much by intensifying the relief 
as by diversifying the topographic forms. 



Fig. 204 — Topographic map of the Andes between Abancay and the Pacific Coast 
at Camana. Compiled from the seven accompanying topographic sheets (see Contents, 
p. xi). Scale 1: 1,000,000. Contour interval 1,000 feet. Longitude west of Greenwich. 
The Central Ranges of the Maritime Cordillera are not confined to the area covered by 
these names. In the one case the term includes all the ranges between Lambrama and 
Euichihua; in the other case, the peaks and ranges from 14° 30' S. to Mt. Coropuna. 






vv^^ 






Mt-SoIima)[a 
20.730 



if' 



Ml G E S 



^S 



'1 '^°°^. 

Slonp Ihttat JZIOO' 



x£3— 



!i.^>:^.'^ii 






lftl\HV,"^'V,f"M^'l'-V\(PA 




I^JS^ 




CAMANA. 

paciIfic ocean 



j'jQ_ 204 Topogrnphic map of the Andes between Abancny and the Pacific Coast 

at Comanfl. Compiled from the seven accompanying topographic sheeta (see Contenta, 
p xi). Scale 1: 1,000,000. Contour interval 1,000 feet. Longitude west of Greenwich. 
The Central Ranges of the Maritime Cordillera are not confined to the area covered by 
these names. In the one caae the term includes all the ranges between Lambrama and 
Huichihua; in the other caae, the peaks and ranges from 14° 30' S. to Mt. Coroptma. 



APPENDIX A 

SURVEY METHODS EMPLOYED IN THE CONSTRUCTION OP 
THE SEVEN ACCOMPANYING TOPOGRAPHIC SHEETS 

By Kai Hendriksen, Topogkapheb 

The main part of the topographical outfit consisted of (1) a 4-inch 
theodolite, Buff and Buff, the upper part detachable, (2) an 18 x 24 inch 
plane-table with Johnson tripod and miero-meteralidade. These instru- 
ments were courteously loaned the expedition by the U. S. Coast and 
Geodetic Survey and the U. S. Geological Survey respectively. 

The method of survey planned was a combination of graphic triangula- 
tion and traverse with the micro-meteralidade. All directions were plotted 
on the plane-table which was oriented by backsight ; distances were deter- 
mined by the micro-meteralidade or triangulation, or both combined; and 
elevations were obtained by vertical angles. Finally, astronomical observa- 
tions, usually to the sun, were taken at intervals of about 60 miles for 
latitude and azimuth to check the triangulation. No observations were 
made for differences in longitude because this would probably not have 
given any reliable result, considering the time and instruments at our 
disposal. Because the survey was to follow very closely the seventy-third 
meridian west of Greenwich, directions and distances, checked by latitude 
and azimuth observation's, undoubtedly afforded far better means of deter- 
mining the longitude than time observations. In other words, the time 
observations made in connection with azimuth observations were not used 
for computing longitudinal differences. Absolute longitude was taken 
from existing observations of principal places. 

Principal topographical points were located by from two to four inter- 
sections from the triangulation and plane-table stations; and elevations 
were determined by vertical angle measurements. Whenever practicable, 
the contours were sketched in the field; the details of the topography 
otherwise depend upon a great number of photographs taken by Pro- 
fessor Bowman from critical stations or other points which it was possible 
to locate on the maps. 



Ckoss-Section Map from Abancat to CamanjC at the Pacific Ocean 

Seven sheets. Scale, 1 : 125,000 ; contour interval, 200 feet. Datum is mean 
sea level. Astronomical control : 5 latitude and 5 azimuth observations as 
indicated on the accompanying topographic sheets. 

315 



316 APPENDIX A 

On September 10th, returning from a reconnaissance survey of the 
Pampaconas River, I joined Professor Bowman's party, Dr. Erving acting 
as my assistant. We crossed the Cordillera Vilcapampa and the Canyon 
of the Apurimac and after a week's rest at Abancay started the 
topographic work near Hacienda San Gabriel south of Abancay. Working 
up the deep valley of Lambrama, observations for latitude and azimuth 
were made midway between Hacienda Matara and Caypi. 

On October 4th we made our camp in newly fallen snow surrounded by 
beautiful glacial scenery. The next day on the high plateau, we passed 
sharp-crested glaciated peaks; a heavy thunder and liail storm broke out 
while I occupied the station at the pass, the storm continuing all the after- 
noon — a frequent occurrence. The camp was made 6 miles farther on, and 
the next morning I returned to finish the latter station. I succeeded in 
sketching the detailed topography just south of the pass, but shortly after 
noon, a furious storm arose similar to the one the day before, and made 
further topograpliic work impossible; to get connection farther on I 
patiently kept my eye to the eye-piece for more than an hour after the 
storm had started, and was fortunate to catch the station ahead in a single 
glimpse. I had a similar experience some days later at station 16,079, 
Antabamba Quadrangle, on the rim of the high-level puna, the storm pre- 
venting all topographic work and barely allowing a single moment in which 
to catch a dim sight of the signals ahead while I kept my eye steadily at 
the telescope to be ready for a favorable break in the heavy clouds and hail. 

At Antabamba we got a new set of Indian carriers, who had orders to 
accompany us to Cotahuasi, the next sub-prefectura. Raimondi's map 
indicates the distance between the two cities to be 35 miles, but although 
nothing definite was stated, we found out in Antabamba that the distance 
was considerably longer, and moreover that the entire route lay at a high 
altitude. 

From the second day out of Antabamba until Huajoiacotas was in sight 
in the Cotahuasi Canyon, a distance of 50 miles, the route lay at an 
altitude of from 16,000 to 17,630 feet, taking in 5 successive camps at an 
altitude from 15,500 to 17,000 feet ; 12 successive stations had the following 
altitudes : 

16,379 feet 
16,852 



17,104 
17,559 
17,675 
17,608 
17,633 
16,305 
17,630 
17,128 
16,794 
16,200 



— highest station occupied. 



APPENDIX A 317 

The occupation of these high stations necessitated a great deal of 
climbing, doubly hard in this rarefied air, and often on volcanoes with a 
surface consisting of bowlders and ash and in the face of violent hailstorms 
that made extremely difficult the task of connecting up observations at 
successive stations. 

At Cotahuasi a new pack-train was organized, and on October 25th I 
ventured to return alone to the high altitudes in order to continue the 
topography at the station at 17,633 feet on the summit of the Maritime 
Cordillera. Dr. Erving was obliged to leave on October 18th and Professor 
Bowman left a week later in order to carry out his plans for a physi- 
ographic study of the coast between Camana and Mollendo. Philippi 
Angulo, a native of Taurisma, a town above Cotahuasi, acted as major- 
domo on this journey. Knowing the trail and the camp sites, I was able 
to pick out the stations ahead myself, and made good progress, returning 
to Cotahuasi on October 29th, three or four days earlier than planned. 
From Cotahuasi to the coast I had the assistance of Mr. Watkins. The most 
trying part of the last section of high altitude country was the great 
Pampa Colorada, crowned by the snow-capped peaks of Solimana and 
Coropuna, reaching heights of 20,730 and 21,703 feet respectively. The 
passing of this pampa took seven days and we arrived at Chuquibamba on 
November 9th. Two circumstances made the work on this stretch 
peculiarly difficult — the scarcity of camping places and the high tempera- 
ture in the middle of the day, which heated the rarefied air to a degree 
that made long-distance shots very strenuous work for the eyes. Although 
our base signals were stone piles higher than a man, I was often forced to 
keep my eye to the telescope for hours to catch a glimpse of the signals ; 
lack of time did not allow me to stop the telescope work in the hottest part 
of the day. 

The top of Coropuna was intersected from the four stations: 
16,344, 15,545, 16,168, and 16,664 feet elevation, the intersections giving 
a very small triangular error. The elevation of Mount Coropuna 's high 
peak as computed from these 4 stations is : 



21,696 


feet 


21,746 


li 


21,714 


it 


21,657 


a 



Mean elevation 21,703 feet above sea level. 



The elevation of Coropuna as derived from these four stations has thus 
a mean error of 18 feet (method of least squares) while the elevation of 
each of the four stations as carried up from mean sea level through 25 
stations — vertical angles being observed in both directions — has an esti- 



318 APPENDIX A 

mated mean error of 30 feet. The result of this is a mean error of 35 feet 
in Coropuna's elevation above mean sea level. 

The latitude is 15° 31' 00" S. ; the longitude is 72° 42' 40" W. of Green- 
wich, the checking of these two determinations giving a result unexpectedly 
close. 

On November 11th azimuth and latitude observations were taken at 
Chuquibamba and two days later we arrived at Aplao in the bottom of the 
splendid Majes Valley. In the northern part of this valley I was prevented 
from doing any plane-table work in the afternoons of four successive days. 
A strong gale set in each noon raising a regular sandgtorm, that made 
seeing almost impossible, and blowing with such a velocity that it was 
impossible to set up the plane-table. 

From Hacienda Cantas to Camana we had to pass the western desert 
for a distance of 45 miles. We were told that on the entire distance there 
was only one camping place. This was at Jaguey de Majes, where there 
was a brook with just enough water for the animals but no fodder. Thus 
we faced the necessity of carrying water for ten men and fodder for 14 
animals in excess of the usual cargo; and we were unable to foretell how 
many days the topography over the hot desert would require. 

Although plane-table work in the desert was impossible at all except in 
the earliest and latest hours of the day, we made regular progress. We 
camped three nights at Jaguey and arrived on the fourth day at Las 
Lomas. 

The next morning, on November 23rd, at an elevation of 2178 feet near 
the crest of the Coast Eange, we were repaid for two months of laborious 
work by a glorious view of the Pacific Ocean and of the city of Camana with 
her olive gardens in the midst of the desert sand. 

The next day I observed latitude and azimuth at Camana and in the 
night my companion and assistant Mr. Watkins and I returned across the 
desert to the railroad at Vitor. 



Conclusions 

The planned methods were followed very closely. In two eases only 
the plane-table had to be oriented by the magnetic needle, the backsights 
not being obtainable because of the impossibility of locating the last sta- 
tion, passing Indians having removed the signals. 

In one case only the distance between two stations had to be deter- 
mined by graphic triangulation exclusively, the base signals having been 
destroyed. Otherwise graphic triangulation was used as a check on 
distances. 

Vertical angles were always measured in both directions with the 
exception of the above-mentioned cases. 

Observations for azimuth were always taken to the sun before and 



APPENDIX A 319 

after noon. The direction used in the azimuth observation was also taken 
with the prismatic compass. The mean of the magnetic declination thus 
found is : East 8° 30' plus. 

Observations for latitude were taken to the sun by the method of 
circum-meridian altitudes, except at the town of Vilcabamba where star 
observations were taken. 

As a matter of course, observations to the sun are not so exact as star 
observations, especially in low latitudes where one can expect to observe 
the near zenith. However, working in high altitudes for long periods, 
moving camp every day and often arriving at camp 2 to 4 hours after 
sunset, I found it essential to have undisturbed rest at night. It was 
beyond my capacity to spend an hour or two of the night in iinding the 
meridian and in making the observation. Furthermore, the astronomic 
observations were to check the topography mainly, the latter being the 
most exact method with the outfit at hand. 

The following table contains the comparisons between the latitude sta- 
tions as located on the map and by observation : 



Camana Quadrangle S 16° 

Coropuna, station 9,691S 15° 

Cotahuasi, " 12,588S 15° 

La Cumbre, " 16,852S 14° 

Lambrama, " 8,341S 13° 

The other observations, with the exception of the one on the Coropuna 
Quadrangle, check probably as well as can be expected with the small and 
light outfit which we used, and under the exceptionally hard conditions of 
work. The observation on the Coropuna Quadrangle just south of 
Chuquibamba is, however, too much out. An explanation for this is that 
the meridian zenith distance was 1° 23' 12" only (in this case the exact 
formula was used in computing) . Of course, an error or an accumulation 
of errors might have been made in the distances taken by the micrometer- 
alidade, but the first cause of eiTor mentioned is the more probable, and 
this is indicated also by the fact that the location on the top of Mount 
Coropuna checks closely with the one determined in an entirely independent 
way by the railroad engineers. 

For the cross-section map from Abancay to Camana, the following 
statistics are desirable : 

' The observation at Camana checks very closely vrith a Peruvian observation the 
Talue of which is S. 16° 37' 00". 



.lap 




Observation 


37' 


34" 


16° 37' 34" ' 


48' 


30" 


(15° 51' 44") 


11' 


40" 


15° 12' 30" 


28' 


10" 


14° 29' 46" 


43' 


18" 


13° 43' 14" 



320 APPENDIX A 

Micrometer traverse and graphic triangulation, with contours, field scale 
1 : 90,000. 

Total time required, days 40.5 

Average distance per days in miles 7.5 

Average number of plane-table stations occupied per day 1,5 

Average area per day in square miles 38. 

Located points per square mUe 0.25 

Approximate elevations in excess of above, per square mile 0.25 

Highest station occupied, feet above sea level 17,675. 

Highest point located, feet above sea level 21,703. 



APPENDIX B 

Fossil Determinations 

A PEW fossil collections were gathered in order that age determinations 
might be made. With the following identifications I have included a few 
fossils (I and II) collected by W. R. Rumbold and put into my hands in 
1907. The Silurian is from a Bolivian locality south of La Paz but in the 
great belt of shales, slates, and schists which forms one of the oldest sedi- 
mentary series in the Eastern Andes of Peru as well as Bolivia. While 
no fossils were found in this series in Peru the rocks are provisionally 
referred to the Silurian. Fossil-bearing Carboniferous overlies them but 
no other indication of their age was obtained save their general position in 
the belt of schists already mentioned. I am indebted to Professor Charles 
Schuchert of Yale University for the following determinations. 

I. Silurian 

San Eoque Mine, southwest slope of Santa Vela Cruz, Canton Ichocu, Prov- 
ince Inquisivi, Bolivia. 

Sent by William R. Rumbold in 1907. 

CUmacograptus f 

PhoKdops trombetana Clarke? 

Chonetes striatellus (Dalman). 

Atrypa marginalis (Dalman) t 

Ccelospira n. sp. 

Ctenodonta, 2 or more species. 

Hyolithes. 

Klcedenia. 

Calymene? 

Dalmanites, a large species with a terminal tail spine. 

Acidaspis. 
These fossils indicate unmistakably Silurian and probably Middle Silurian. 
As all are from blue-black shales, brachiopods are the rarer fossils, while bivalves 
and trilobites are the common forms. The faunal aspect does not suggest relation- 
ship with that of Brazil as described by J. M. Clarke and not at all with that of 
North America. I believe this is the first time that Silurian fossils have been 
discovered in the high Andes. 

II. Lower Devonian 

Near north end of Lake Titicaca. 

Leptoeoslia flabellites (Conrad), very common. 
Atrypa reticularis (Linneeus) ? 

321 



322 • APPENDIX B 

This is a part of the well-known and widely distributed Lower Devonian fauna 
of the southern hemisphere. 

III. Upper Carboniferous 

All of the Upper Carboniferous lots of fossils represent the well-known 
South American fauna first noted by d'Orbigny in 1842, and later added to by 
Orville Derby. The time represented is the equivalent of the Pennsylvanian of 
North America. 

Huascatay between Pasaje and Huancarama. 
Crinoidal limestone. 
Trepostomata Bryozoa. 
Pohjpora. Common. 

Streptorhynehus halliamis Derby. Common. 
Chonetes glaber Geinitz. Rare. 
Productus humboldti d'Orb. Rare. 
" cora d'Orb. Rare. 

" chandlessii Derby. 

" sp. undet. Common. 

" sp. undet. " 

Spirifer condor d'Orb. Common. 
Hustedia mormoni {yisxaou) . Rare. 
Seminula argent ea (Shepard). " 
Pampaconas, Pampaconas valley near Vilcabamba. 
Lophophyllum? 
Bhombopora, etc. 
Productus. 

Camarophoria. Common. 
Spirifer condor d'Orb. 
Hustedia mormoni (Marcou). 
Euomphdlus. Large form. 
Pongo de Mainique. Extreme eastern edge of Peruvian Cordillera. 
Loplwphyllum. 
Productus chandlessii Derby. 

" cora d'Orb. 

Orthotetes correanus (Derby). 
Spirifer condor d'Orb. 
River bowlders and stones of Urubamba river, just beyond eastern edge of 
Cordillera at mouth of Ticumpinea river. (Detached and transported by stream 
action from the Upper Carboniferous at Pongo de Mainique.) 
Mostly Trepostomata Bryozoa. 
Many Productus spines. 
Productus cora d'Orb. 
Camarophoria. Same as at Pampaconos. 
Productus sp. undet. 
Cotahuasi A. 

Lophophyllum. 
Productus peruvianus d'Orb. 
" sp. undet. 



APPENDIX B 323 

Camarophoria. 
Pugnax near utah (Marcou). 
Seminula argentea (Shepard) ? 
Cotahuasi B. 

Productus cora d'Orb. 

" near semireticulatus (Martin). 

IV. Comanchian or Lower Cretaceous 

Near Chuquibambilla. 

Pecten near quadricostatus Sowerby. 

Undet. bivalves and gastropods. 

The echinid Laganumf colomhianum d'Orb. A clypeasterid. 
This Lower Cretaceous locality is evidently of the same horizon as that of 
Colombia illustrated by d'Orbigny in 1842 and described on pages 63-105. 



APPENDIX C 



KEY TO PLACE NAMES 



Abancay, town, lat. 12° 35', Figs. 20, 204. 
Abra Tocate, pass, between Yavero and 

Urubamba valleys, leaving latter at 

Rosalina, ( Fig. 8 ) . See also Fig. 55. 
Anta, town, lat. 13° 30', Fig. 20. 
Antabamba, town, lat. 14° 20', Figs. 20, 

204. 
Aplao, town, lat. 16°, Figs. 20, 204. 
Apurimac, river, Fig. 20. 
Arequipa, town, lat. 16° 30', Fig. 66. 
Arica, town, northern Chile, lat. 18° 30'. 
Arma, river, tributary of Apurimac, lat. 

13° 25', (Fig. 20) ; tributary of OcoSa, 

lat. 15° 30', (Fig. 20). 
Arma, village, lat. 13° 15', Fig. 20. See 

also Fig. 140. 
Auquibamba, hacienda, lat. 13° 40', Fig. 

204. 

Callao, town, lat. 12°, Fig. 66. 

Camana, to^vn, lat. 16° 40', Figs. 20, 66, 
204. 

Camisea, river, tributary of Urubamba en- 
tering from right, lat. 11° 15'. 

Camp 13, lat. 14° 30'. 

Cantas, hacienda, lat. 16° 15', Fig. 204. 

Caraveli, to^vn, lat. 16°, Fig. 06. 

Catacaos, town, lat. 5° 30', Fig. 66. 

Caylloma, town and mines, lat. 15° 30', 
Fig. 66. 

Caypi, village, lat. 13° 45'. 

Central Ranges, lat. 14°, Fig. 20. See also 
Fig. 157. 

Cerro Azul, town, lat. 13°, Fig. 66. 

Chachani, mt., overlooliing Arequipa, lat. 
16° 30', (Fig. 66). 

Chaupimayu, river, tributary of Uru- 
bamba entering at Sahuayaco, q.v. 

Chili, river, tributary of Vitor River, lat. 
16° 30', (Fig. 66). 

Chinche, hacienda, Urubamba Valley 
above Santa Ana, lat. 13°, (Fig. 20). 

Chira, river, lat. 5°, Fig. 66. 

Choclococha, lake, lat. 13° 30', Figs. 66, 68. 

Choqquequirau, ruins, canyon of Apurimac 



above junction of Pachachaca River, lat. 

13° 25', (Fig. 20). 
Choquetira, village, lat. 13° 20', Fig. 20. 

See also Fig. 136. 
Chosica, village, lat. 12°, Fig. 66. 
Chuquibamba, town, lat. 15° 50', Figs. 20, 

204. 
Chuquibanibilla, village, lat. 14°, Figs. 20, 

204. 
Chuquito, pass, Cordillera Vilcapampa be- 
tween Arma and Vilcabamba valleys, 

lat. 13° 10', (Fig. 20). See also Fig. 

139. 
Coast Range, Figs. 66, 204. 
Cochabamba, city, Bolivia, lat. 17° 20', 

long. 66° 20'. 
Colorada, pampa, lat. 15° 30', Fig. 204. 
Colpani, village, lower end of Canyon of 

Torontoy (Urubamba River), lat. 13° 

10'. See Fig. 158. 
Copacavana, village, Bolivia, lat. 16° 10', 

long. 69° 10'. 
Coribeni, river, lat. 12° 40', Fig. 8. 
■ Coropuna, mt., lat. 15° 30', Figs. 20, 204. 
Corralpata, village, Apurimac Valley near 

Incahuasi. 
Cosos, village, lat. 16°, Fig. 204. 
Cotabambas, town, Apurimac Valley, lat. 

13° 45', (Fig. 20). 
Cotahuasi, town, lat. 15° 10', Figs. 20, 

204. 
Cuzco, city, lat. 13° 30', Fig. 20. 

Echarati, hacienda, on tlie Urubamba 
River between Santa Ana and Rosalina, 
lat. 12° 40'. See inset map. Fig. 8, 
and aho Fig. 54. 

HuadquiiSa, hacienda, Urubamba River 

above junction with Vilcabamba, lat. 

13° 10', (Fig. 20). See also Fig. 158. 
Huadquirca, village, lat. 14° 15', Figs. 20, 

204. 
Huaipo, lake, north of ^inta, lat. 13° 25', 

(Fig. 20). 



324 



APPENDIX C 



325 



Huambo, village, left bank Paehaehaca 
River between Huanoarama and Pasaje, 
lat. 13° 35', (Fig. 20). 

Huancarama, town, lat. 13° 40', Fig. 20. 

Huancarqui, village, lat. 16° 5', Fig. 204. 

Huascatay, village, left bank of Apurimac 
above Pasaje, lat. 13° 30', (Fig. 20). 

Huaynacotas, village, lat. 15° 10', Fig. 204. 

Huichihua, village, lat. 14° 10', Fig. 204. 

(Tablazo de) lea, plateau, lat. 14°-15° 30', 

Fig. 66. 
lea, town, lat. 14°, Figs. 66, 67. 
Incahuasi, village, lat. 13° 20', Fig. 20. 
Iquique, town, northern Chile, lat. 20° 15'. 
(Pampa de) Islay, south of Vitor River, 

(Fig. 66). 

Jaguey, village, Pampa de SUiuas, q.v. 

La Joya, pampa, station on Jlollendo- 

Puno R.R., 16° 40', (Fig. 66). 
Lambrama, village, lat. 12° 50', Fig. 20. 
Lima, city, lat. 12°, Fig. 66. 

Machu Piechu, ruins, gorge of Torontoy, 

q.v., lat. 13° 10'. 
Majes, river. Fig. 204. 
Manugali, river, tributary of Urubamba 

entering from left above Puviriari 

River, lat. 12° 20', (Fig. 8). 
Maritime Cordillera, Fig. 204. 
Matara, village, lat. 14° 20', Fig. 204. 
(El) Misti, mt., lat. 16° 30', Fig. 66. 
JMollendo, town, lat. 17°, Fig. 66. 
Moquegua, town, lat. 17°, Fig. 66. 
Moroeoeha, mines, lat. 11° 45', Fig. 66. 
Mulanquiato, settlement, lat. 12° 10', 

Fig. 8. 

Occobamba, river, uniting with Yanatili, 
q.v. 

Ocona, river, lat. 15°-16° 30', Figs. 20, 66. 

Ollantaytambo, village, Urubamba River 
below Urubamba town, lat. 13° 15', 
(Fig. 20), and see inset map, Fig. 8. 

Pabellon, hacienda, Urubamba River above 
Rosalina, (Fig. 20). See also Fig. 55. 

Pacasmayo, town, lat. 7° 30', Fig. 66. 

Pachatusea (Pachatusun), mt., overlook- 
ing Cuzco to northeast, lat. 13° 30'. 

Paehitea, river, tributary of Ucayali en- 
tering from left, lat. 8° 50'. 



Paita, town, lat. 5°, Fig. 66. 

Pampacolea, village, south of Coropuna, 
q.v. 

Pampaconas, river, known in lower course 
as Cosireni, tributary of Urubamba 
River, (Fig. 8). Source in Cordillera 
Vileapampa west of Vilcabamba. 

Pampas, river, tributary of Apurimac en- 
tering from left, lat. 13° 20'. 

Panta, mt., Cordillera Vileapampa, north- 
west of Arma, lat. 13° 15', (Fig. 20). 
See also Fig. 136. 

Panticalla, pass, Urubamba Valley above 
Torontoy, lat. 13° 10'. 

Pasaje, hacienda and ferry, lat. 13° 30', 
Fig. 20. 

Paucartambo (Yavero), river, q.v. 

Paucartambo, town, head of Paucartambo 
(Yavero) River, lat. 13° 20', long. 71° 
40'. Inset map. Fig. 8. 

Pichu-Pichu, mt., overlooking Arequipa, 
lat. 16°, (Fig. 66). 

Pilcopata, river, tributary of Upper Jladre 
de Dios east of Paucartambo, lat. 13°. 

Pini-pini, river, tributary of Upper Madre 
de Dios east of Paucartambo, lat. 13°. 

Pisco, town, lat. 14°, Fig. 66. 

Piura, river, lat. 5°-6°, Fig. 66. 

Piura, town, lat. 5° 30', Fig. 60. 

Pomareni, river, lat. 12°, Fig. 8. 

Pongo de Mainique, rapids, lat. 12°, 
Fig. 8. 

Pucamoco, hacienda, Urubamba River, be- 
tween Santa Ana and Rosalina, (Fig. 
20). 

Puquiura, village, lat. 13° 5', Fig. 20. 
See also Fig. 158. Distinguish Puqura 
in Anta basin near Chizco. 

Puqura, village, Anta basin, east of Anta, 
lat. 13° 30', (Fig. 20). 

Quilca, town, lat. 16° 40', Fig. 66. 
Quillagua, village, northern Chile, lat. 
21° 30', long. 69° 35'. 

Rosalina, settlement, lat. 12° 35', Fig. 8. 
See also Fig. 20. 

Sahuayaco, hacienda, Urubamba Valley 
above Rosalina, (Fig. 20). See also 
Fig. 55. 

Salamanca, town, lat. 15° 30', Fig. 20. 

Salaverry, town, lat. 8°, Fig. 66. 

Salcantay, mt., lat. 13° 20', Fig. 20. 



326 



APPENDIX C 



San Miguel, bridge, canyon of Torontoy 

near Machu Picchu, lat. 13° 10'. 
Santa Ana, hacienda, lat. 12° 50', Fig. 20. 
Santa Ana, river, name applied to the 

Urubamba in the region about hacienda 

Santa Ana. 
Santa Lucia, mines, lat. 16°, Fig. 66. 
Santo Anato, hacienda. La Sama's hut, 

12° 35', Fig. 8. 
Sihuas, Pampa de, lat. 16° 30', Fig. 204. 
Sillilica, Cordillera, east of Iquique, 

northern Chile. 
Sintulini, rapids of Urubamba River 

above junction of Pomareni, lat. 12° 10', 

(Fig. S). 
Sirialo, river, lat. 12° 40', Fig. 8. 
Soiroccoeha, mt., Cordillera Vileapampa 

north of Arma, lat. 13° 15', (Fig. 20). 
Solimana, mt., lat. 15° 20', Fig. 204. 
Soray, mt., Cordillera Vileapampa, south- 
east of Mt. Saloantay, lat. 13° 20', 

(Fig. 20). 
Sotospampa, village, near Lambrama, lat. 

13° 50', (Fig. 204). 
Sullana, town, Chira River, lat. 5°, (Fig. 

66). 

Taurisma, village, lat. 15° 10', Fig. 204. 

Ticumpinea, river, tributary of Uru- 
bamba entering from right below Pongo 
de Mainique, lat. 11° 50', (Fig. 8). 

Timpia, river, tributary of Urubamba en- 
tering from right, lat. 11° 45'. 

Tono, river, tributary of Upper Madre de 
Dios, east of Paucartambo, lat. 13°. 

Torontoy, canyon of the Urubamba be- 
tween the villages of Torontoy and Col- 
pani, lat. 13° 10'-13° 15'. 

Torontoy, village at the head of the 



canyon of the same name, lat. 13° 15'. 

See inset map, Fig. 8. 
Tumbez, town, lat. 4° 30', Fig. 60. 
Tunari, Cerro de, mt., northwest of Co- 

chabamba, q.v. 

Urubamba, river, Fig. 20. 

Urubamba, town, lat. 13° 20', Fig. 20. 

Vilcabamba, river, tributary' of Urubamba 
River entering from left above Santa 
Ana, lat. 13°, Fig. 8. See also Fig. 158. 

Vilcabamba, village, lat. 13° 5', Fig. 20. 
-See aho Fig. 158. 

Vilcanota, Cordillera, southern Peru. 

Vilcanota, river, name applied to Uru- 
bamba above lat. of Cuzco, 13° 30', (Fig. 
20). 

Vileapampa, Cordillera, lat. 13° 20', Fig. 
20. 

Vilque, town, southern Peru, lat. 15° 50', 
long. 70° 30'. 

Vitor, pampa, lat. 16° 30', Fig. 66. 

Vitor, river. Fig. 66. 

Yanahuara, pass, between Urubamba and 

Yanatili valleys, lat. 13° 10'. 
Yanatili, river, tributary of Urubamba en- 
tering from right above Rosalina, (Fig. 

20). See also Fig. 55. 
Yavero (Paucartambo), river, tributary 

of Urubamba entering from right, lat. 

12° 10', Fig. 8. 
Yavero, settlement, at junction of Yavero 

and Urubamba rivers, lat. 12° 10', 

Fig. 8. 
Yunguyo, town, southern Peru, lat. 16° 

20', long. 69° 10'. 
Yuyato, river, lat. 12° 5', Fig. 8. 



INDEX 



Abancay, 32, 62, 64, 78, 92, 93, 181, 189, 
221, 243; suppressing a revolution, 89- 
91; temperature curve (diagr.), opp. p. 
180 

Abancay basin, 154 

Abancay to Camanfi cross-section map, 
work, observation and statistics, 315 

Abra Toeate, 73, 80, 81; topography and 
vegetation from (ill.)> opp. p. 19 

Abra de Malaga, 276 

Acosta, 205 

Adams, G. I., 255 

Agriculture, 74-76, 152 

Aguardiente, 74. See Brandy 

Alcobol, 5, 6 

Alluvial fans, 60-63, 70, 270 

Alluvial fill, 270-273; view in Majes 
Valley (ill.), opp. p. 230 

Alpacas, 5, 52 

Alto de los Huesos (ill.), opp. p. 7 

Amazon basin, Humboldt's dream of con- 
quest, 33-35; Indian tribes, 36 

Amazonia, 20, 26 

Ancachs, 171 

Andabuaylas, 89 

Andrews, A. C, 295 

Angulo, Pbilippi, 317 

Anta, 187, 189, 190 

Anta basin, 62, 108, 197; geology, 250; 
view looking north from hill near Anta 
(ill.), opp. p. 184 

Antabamba, 52, 53, 95, 96, 99, 101, 189, 
197, 243, 303, 316; Governor, 95-99, 
100-101; Lieutenant Governor, 96-99, 
101; sketch section, 243 

Antabamba Canyon, view across (ill.), 
opp. p. 106 

Antabamba Quadrangle, 316, opp. p. 282 
(topog. sheet) 

Antabamba region, geologic sketch map 
and section, 245 

Antabamba Valley, 96 

"Antis," 39 

Aplao, 106, 115, 116, 181, 226, 231, 255, 
256, 257, 273, 318; composite structure 
section (diagr.), 259; temperature 
curve (diagr.), 181 



Aplao Quadrangle (topog. sheet), opp. p. 

120 
Appendix A, 315 
Appendix B, 321 
Appendix C, 324 
Apurimac, 51, 57, 60, 94, 153, 154; 

crossing at Pasaje (ills.), opp. p. 91; 

regional diagram of canyoned country, 

58 
Apurimac Canyon, 189; cloud belt (ill.), 

opp. p. 150 
Arequipa, 52, 89, 92, 117, 120, 137, 

284; glacial features near (sketches), 

280 
Argentina, 93 
Arica, 130, 132, 198 
Arma, 67, 189. 212-214 
Arrieros, Pampa de, 280 
Asymmetrical peaks (ill.), opp. p. 281 
Asymmetry, 305-313; cross-section of ridge 

(diagr.), 306; postglacial volcano 

(diagr.), 306 
Auquibamba, 93 
Avalanches, 290 

Bailey, S. I., 284 

Bandits, 95 

Basins, 60, 154; regional diagram, 61; 

climatic cross-section (diagr.), 62 
Batholith, Vileapampa, 215-224 
Belaunde brothers, 116 
Bergschrunds, 294-305 
Bingham, Hiram, ix, 104, 157 
Block diagram of physiography of Andes, 

186 
Boatmen, Indian, 13 
Bogota, Cordillera of, 205 
Bolivia, 93, 176, 190, 193, 195, 240, 241, 

249, 322; snowline, 275-277 
Bolivian boundary, 68 
Border valleys of the Eastern Andes, 68- 

87 
Borneo, 206 

Bo^vman, Isaiah, 8, 316 
Brandy, 74, 75, 76, 82-83 
Bravo, Jos6, 245 
Biunstead, A. H., ix 



327 



328 



INDEX 



Cacao, 74, 83 

Cacti, 150; arboreal (ill.), opp. p. 90 

CalchaquI Valley, 250 

Callao, 118; cloudiness ( with diagr. ) , 133; 
temperature (with diagr.), 126-129; 
wind roses (diagrs.), 128 

Camanfi, 21, 112, 115, 116, 117, 118, 140- 
141, 147, 181, 225, 226, 227, 266, 313; 
coastal Tertiary, 253, 254; plain of, 229; 
temperature curve (diagr.), 181 

Camanfi Quadrangle (topog. sheet), opp. 
p. 114 

Camana Valley, 257 

Camana-Vitor region, 117 

Camino del PeCon, 110 

Camisea, 36 

Camp 13, 100, 180, 181; temperature curve 
(diagr.), 180 

Campas, 37 

Canals for bringing water, 59, 60, 155; 
projected, Maritime Cordillera (diagr.), 
118 

Cantas, 115, 116, 226, 253, 257, 273, 318 

Canyon walls (ills.), opp. p. 218 

Canyoned country, regional diagram, 58; 
valley climates (diagr.), 59 

Canyons, 60, 72, 73, 197, 219; Majes River 
(ill.), opp. p. 230; topographic condi- 
tions before formation of deep canyons 
in Maritime Cordillera (ill.), opp. p. 
184 

Caraveli, climate data, 134-136; wind 
roses (diagrs.), 136 

Carboniferous fossils, 323 

Carboniferous strata, 241-247; hypo- 
thetical distribution of land and sea 
(diagr.), 246 

Cashibos, 37 

Catacaoa, 119 

Cattle tracks (ill.), opp. p. 226 

Caucho, 29 

Caylloma, 164, 165 

Cay pi, 316 

Central Ranges, asymmetrical peaks (ill.), 
opp. p. 281; glacial features with lateral 
moraines (ill.), opp. p. 269; glacial 
topography between Lambrama and 
Antabamba (ill.), opp. p. 280; steep 
cirque walls (ill.), opp. p. 286 

Cerro Azul, 118 

Cerro de Tunari, 176 

Chachani, 280, 284 

Chanchamayo, 77 

Character. Bee Human character 



Chaupimayu Valley, 77 
Chicha, 86 

Chile, 130, 132, 193, 260 
Chili River, 120 

Chili Valley, opp. p. 7 (ill.), 117 
Chimborazo, 281 
Chinche, 271, 272 

Chira River, depth diagram, 119, 120 
Chirumbia, 12 
Choclococha, Lake, 120 
Chonta Campas, 37 
Choqquequirau, 154 

Choquetira, 66, 67, 211; bowldery fill be- 
low, 269; glacial features, 206-207 
Choquetira Valley, moraine (ill.), opp. p. 

208 
Chosica, 136, 137; cloudiness (diagr.), 

138 
Chuno, 57 
Chuntaguirus, 41 
Chuquibamba, 54, 72, 107, 110, HI, 112, 

115, 116, 273, 317-319; sediments, 258 
Chuquibambilla, 53, 189, 220, 221, 222, 

236, 243; alluvial fill (diagr.), 272; 

Carboniferous, 244; fossils, 323 
Chuquito pass, crossing (ill.), opp. p. 7; 

glacial trough (ill.), opp. p. 205 
Cirque walls, steep (ill.), opp. p. 286 
Cirques, 294-305; development (diagr.), 

300 ; development, further stages 

(diagr.), 301; mode of formation 

(diagr.), 297 
Clarke, J. M., 321 
Clearing in forest (ill.), opp. p. 25 
Climate, coast, 125-147; eastern border, 

147-153; Inter- Andean valleys, 153-155; 

see also Meteorological records 
Climatic belts, 121-122; map, 123 
Climatology, 121-156 
Cliza, 276 
Cloud-banners, 16 
Cloud belt, 143, opp. p. 150 (ill.) 
Cloudiness, 132; Callao (with diagr.), 

133; desert station near Caraveli 

(diagrs.), 137; Machu Picchu, 160; 

Santa Lucia (diagr.), 169 
Clouds, Inter-Andean Valley, 155; Santa 

Ana (ill.), opp. p. 180; Santa Lucia, 

168; types on eastern border of Andes 

(diagrs.), 148; see also Fog 
Coast Range, 111, 113, 114, 116, 118, 225- 

232; climate, 122-147; direction, 207; 

diagram to show progressive lowering 

of saturation temperature in a desert. 



INDEX 



329 



127; geology, 258; view between Mol- 
lendo and Arequipa in June {ill.)> opp. 
p. 226; wet and dry seasons (diagrs.), 
132 

Coastal belt, map of irrigated and irriga- 
ble land, 113 

Coastal desert, 110-120; regional diagram 
of physical relations, 112; see also 
Deserts 

Coastal planter, 6 

Coastal region, topographic and climatic 
provinces (diagr. ), 125 

Coastal terraces, 225-232 

Coca, 74, 77, 82-83 

Coca seed beds (ill.), opp. p. 74 

Cochabamba, 93; temperature (diagrs. of 
ranges), insert opp. p. 178; weather 
data, 176-178 

Cochabamba Indians, 276 

Colombia, 205 

Colorada, Pampa de, 114, 317 

Colpani, 72, 215, 216, 222, 223; from ice 
to sugar cane (ill.), opp. p. 3 

Comanchian fossils, 323 

C6mas, 155 

Compania Gomera de Mainique, 29, 31, 32 

Concession plan, 29 

Conibos, 44 

Contador, 84-85 

Copacavana, 176 

Cordilleras, 4, 6, 20, 197 

Coribeni, 15 

Corn, 57, 59, 62 

Coropuna, 109, 110, 112, 202, 253, 317, 
319; elevation, 317; glaciation, 307; 
snowline, 283-285 

Coropuna expedition, 104 

Coropuna Quadrangle, 197, opp. p. 188 
(topog. sheet), 319 

Corralpata, 51, 59 

Cosos, 231 

Cotabambas, 78 

Cotahuasi, 4, 5, 52, 54, 60, 97, 101, 103, 
104, 180, 197, 199, 316, 317; alluvial 
fill, 272; fossils, 322; geologic sketch 
maps and cross-section, 247 ; rug weaver 
(ill.), opp. p. 68; snowline above, 282- 
283; temperature curve (diagr.), 180; 
view (ill.), opp. p. 57 

Cotahuasi Canyon, 247, 248, 316 

Cotahuasi Quadrangle (topog. sheet), opp. 
p. 192 

Cotahuasi Valley, geology, 258 

Cotton, 76, 116, 117 



Crest lines, asymmetrical, 305-313 

Cretaceous formations, 247-251 

Cretaceous fossils, 323 

Crucero Alto, 188 

Cuzco, 8, 10, 21, 52, 62, 63, 92, 102, 107, 

193, 197; railroad to Santa Ana, 09-70; 

snow, 276; view (ill.), opp. p. 60 
Cuzco basin, 61, 62, 154, 251; slopes at 

outlet (diagr.), 185 

Deformations. See Intrusions 

Derby, Orville, 322 

Desaguadcro Valley, 193 

Deserts, cloudiness (diagrs.), 137; ram, 
138-140; sea-breeze in, 132; tropical for- 
est, 36-37; wind roses (diagrs.), 136 

Diagrams. See Regional diagrams 

Dikes, 223 

Drunkenness, 103, 105-106, 108 

Dry valleys, 114-115 

Dunes, 114, 254; Majes Valley, 262-267; 
movement, 132; superimposed (diagrs.), 
265 

Duque, Senor, 78 

Eastern Andes, 204-224; regional dia- 
gram, 22 

Eastern border, climate, 147-153 

Eastern valley planter, 3 

Eastern valleys, 68-87 ; climate cross-sec- 
tion (diagr.), 79 

Echarati, 10, 77, 78, 80, 82; plantation 
scene (ill.), opp. p. 75 

Ecuador volcanoes, 281 

Epiphyte (ill.), opp. p. 78 

Erdis, E. C, 158 

Erosion, 192-195, 210, 211, 305; see also 
Glacial erosion ; Nivation 

Erving, Dr. W. G., 13, 101, 316, 317 

Faena Indians, 76, 83-87 

Feasts and fairs, 175-176 

Ferries, 147 

Fig tree (ill.), opp. p. 75 

Floods, 151 

Fog, 132, 139, 143; conditions along coast 
from Camana to MoUendo, 144-145; see 
also Clouds 

Forest dweller, 1 

Forest Indians. See Machigangas 

Forests, clearing (ill.), opp. p. 25; dense 
ground cover, trees, epiphytes, and 
parasites (ill.), opp. p. 155; moss- 
draped trees (ill.), opp. p. 24; moun- 



330 



INDEX 



tain, 148-153; mule trail (ill.), opp. p. 

18; tropical, near Pabellon (ill.), opp. 

p. 150; tropical vegetation (ill.), opp. p. 

18; type at Salmayaco (ill.), opp. p. 90 
Fossils, 245, 321; list of, by geologic 

periods and localities, 321 
Frankland, 278, 309 
Frost line, 56-57 

Garua, 132 

Geographical basis of revolutions and of 
human character, 88-109 

Geologic dates, 195-196; Majes Valley, 
258, 261; west coast fault, 248-249 

Geologic development. See Physiographic 
and geologic development 

Gilbert, G. K., 300, 302, 305 

Glacial deposits, 268 

Glacial erosion. Central Andes, 305-313; 
composite sketch of general conditions, 
312; graphic representation of amount 
during glacial period, 311 

Glacial features, 274-313; Arequipa 
(sketches), 280; Central Ranges; lat- 
eral moraines (ill.), opp. p. 269; eastern 
slopes of Cordillera Vilcapampa (map), 
210 

Glacial retreat, 208-214 

Glacial sculpture, heart of the Cordillera 
Vilcapampa (map), 212; southwestern 
flank of Cordillera Vilcapampa (map), 
207 

Glacial topography between Lambrama 
and Antabamba (ill.), opp. p. 280; 
Maritime Cordillera, north of divide on 
73d meridian (ill.), opp. p. 281 

Glacial trough, view near Chuquito pass 
(ill.), opp. p. 208 

Glaciation, 64, 271; Sierra Nevada, 305; 
Vilcapampa, 204-214; Western Andes, 
202 

Glaciers, Panta Mountain (ill.), opp. p. 
287; view (ill.), opp. p. 205 

Gomara, 34 

Gonzales, Sefior, 78 

Government, bad, 95 

Gran Pajonal, 37 

Granite, 215-224; see also Intrusions 

Grass (ill.), opp. p. 154 

Gregory, J. W., 205 

Hacendado, 55, 60 
Haciendas, 78, 83, 86 
Hann, J., 126, 176, 278 



Hendriksen, Kai, 98, 315 

Hettner, 205 

Hevea, 29 

Highest habitations in the world, 52, 96; 

regional diagram of, 50; stone hut (ill.), 

opp. p. 48 
Highland shepherd, 4 
Highlands, 46 
Hobbs, W. H., 286, 287 
Horses, 66, opp. p. 91 (ill.) 
Huadquiiia, 70, 71, 72, 75, 82, 86, 219; 

hacienda (ill.), opp. p. 73; terraces, 

272 
Huadquirca, 243 
Huaipo, Lake, 250, 251 
Huallaga basin, 153 
Huambo, 243 
Huancarama, 64, 87, 189, 243, 303; view 

(ill.), opp. p. 106 
Huancarqui, 257 
Huari, 176 
Huascatay, 189, 242, 243; Carboniferous, 

244; fossils, 322 
Huaseo basin, 275 
Huaynacotas, 103, 316; terraced valley 

slope (ill.), opp. p. 56; terraced valley 

slopes (ill.), opp. p. 199 
Huichihua, 278; alluvia! fill (diagr.), 272; 

(ill.), opp. p. 07 
Human character, geographic basis, 88- 

109 
Humboldt, 33-35, 286 
Humboldt Current, 126, 143 
Huts, 103; highest in Peru (ill.), opp. p. 

48; shepherds', 47, 48, 52, 55 

lea Valley, 120; irrigated and irrigable 
land (diagr.), 118 

loe erosion. See Glacial erosion 

Incahuasi, 51, 155, 285 

Incas, 39, 44, 40, 62, 63, 68, 77, 109, 175 

Incharate, 78 

Indian boatmen, 13 

Indians, as laborers, 26-28, 31-32; basin 
type, 63-64; forest, see Machigangas; 
life and tastes, 107-108; mountain, 46- 
67, 101-102; plateau, 40-41, 44-45, 100, 
106-109; troops, 90, 91; wrongs, 14, 102 

Ingomwimbi, 200 

Instruments, surveying, 315 

Inter-Andean valleys, climate, 153-155 

Intermont basin. See Basins 

Intrusions, deformations north of Lam- 
brama (diagr.), 243; deformative ef- 



INDEX 



331 



fects on limestone strata near Chuqui- 
bambilla (diagr.), 221; lower Uru- 
bamba Valley (geologic sketch map), 
237; overthrust folds in detail near 
Chuquibambilla (diagr.), 222; princi- 
ples, 217-219 

Intrusions, Vilcapampa, deformative ef- 
fects near Puquiura (diagr.), 216; rela- 
tion of granite to schist near Colpani 
(with diagr.), 216 

Iquique, wind roses (diagrs.), 131 

Irrigation, 72, 76, 80, S2; coastal belt 
(map), 113; coastal desert, 119-120; 
lea Valley (diagr.), 118 

Islay, Pampa de, 114 

Italians, 18, 81 

Jaguey, 254, 255, 318 

Jesuits, 68 

Johnson, W. D., 213, 295, 296, 299, 300 

Kenia, Mt., 206, 274 
Kerbey, Major, 8, 10 
Kibo, 206, 274 
Kilimandjaro, 205, 206 
Kinibalu, 206 
Kriiger, Herr, 157 

Labor, 26-28, 31-32, 42-43, 74-75, 83-84 
La Cumbre Quadrangle, 197, 202, opp. p. 

202 (topog. sheet) 
La Joya, 132, 133; cloudiness (diagr.), 

134; temperature curves (diagr.), 134; 

wind roses (diagrs.), 135 
Lambrama, 90, 92, 285, 316; camp near 

(ill.), opp. p. 6 
Lambrama Quadrangle (topog. sheet), 

opp. p. 304 
Lambrama Valley, deformation types 

(diagr.), 243 
Land and sea. Carboniferous hypothetical 

distribution compared with present 
(diagr.), 246 
Landscape, 183-198 
Lanius, P. B., 13 
La Paz, 93, 109, 276, 321 
La Sama, 12, 13, 40 
Las Lomas, 318 
Lava flows, 199 
Lava plateau, 197, 199, 307-308; regional 

diagram of physical conditions, 55; 

summit above Cotahuasi (ill.), opp. p. 

204 
Lavas, volume, 201 



Lima, 92, 93, 118, 137, 138; cloud, 132, 

143; temperature, 126 
Limestone, sketch to show deformed, 243 
Little, J. P., 135, 157 
Llica, 275 

Lower Cretaceous fossils, 323 
Lower Devonian fossils, 321 

Machigangas, 10, 11, 12, 14, 18, 19, 31, 
36-45, 81; ornaments and fabrics (ill.), 
opp. p. 27; trading with (ill.), opp. p. 
26 

Machu Picchu, 72, 220; weather data 
(with diagr.), 158-160 

Madeira-Mamorg railroad, 33 

Madre de Dios, 1, 2, 33 

Majes River, 147, 225, 227, 266, 267; 
Canyon (ill.), opp. p. 230 

Majes Valley, 106, 111, 116, 117, 120, 226, 
227, 229-231, 318; alluvial fill, 273; date 
of formation, 258, 261 ; desert coast 
(ill.), opp. p. 110; dunes, 262-267; 
erosion and uplift, 261; lower and upper 
sandstones (ill.), opp. p. 250; sedi- 
ments, 255; snowline, 283; steep walls 
and alluvial fill (ill.), opp. p. 230; 
structural details near Aplao (sketch 
section), 255; structural details on 
south wall near Cantas (sketch section), 
257; structural relations at Aplao 
(field sketch), 256; Tertiary deposits, 
253-254; wind, 130; view below Cantas 
(ill.), opp. p. 110; view down canj'on 
(ill.), opp. p. 144 

Malaria, 14, 38 

Maranon, 41, 59 

Marcoy, 79 

Marine terrace at Mollendo (ill.), opp. p. 
226 

Maritime Cordillera, 52, 199-203, 233; 
asymmetry of ridges, 308-309; glacial 
features, 307; glacial topography north 
of divide on 73d meridian ( ill. ) , opp. p. 
281; pre-volcanic topography, 200; post- 
glacial volcano, asymmetrical (diagr.), 
306; regional diagrams, 50, 52; test of 
explanation of cirques, 303; volcanoes, 
tuffs, lava flows (ill.), opp. p. 204; 
western border rocks (geologic section), 
257; see also Lava plateau 

Matara, 99, 316 

Matthes, F. E., 280, 287, 289 

Mature slopes, 185-193; between Ollantay- 
tambo and Urubamba (ill.), opp. p. 



332 



INDEX 



185; dissected, north of Anta (ill.), 
opp. p. 185 

Mawenzi, 206 

Meanders, 16, 17 

MSdanos, 114 ' ■ 

Mendoza, Padre, 11 

Mer de Glaee, 203 

Meteorological records, 157-181 

Mexican revolutions, 93 

Middendorf, 143 

Miller, General, 41, 78, 147 

Minchin, 241 

Misti, El, opp. p. 7 (ill.), 284 

Molina, Cbristoval de, 175 

Mollendo, 93, 105, 117; cloud belt, 143; 
cloudiness (diagr.), 134; coastal ter- 
races, 225; humidity, 133; marine ter- 
race (ill.), opp. p. 226; profile of 
coastal terraces (diagr.), 227; tem- 
perature curves (diagr.), 134; 'wind 
roses (diagrs. ), 129 

Mollendo- Arequipa railroad, 117 

Mollendo rubber, 32 

Montana, 148, 149, 153 

Moquegua, 117; geologic relations 
(diagr.), 255 

Moraines, 207, 210-211; Choquetira Valley 
(ill.), opp. p. 208; view (ill.), opp. p. 
208 

Morales, Senor, 11 

Morococha, temperature (diagrs. of 
ranges), insert opp. p. 172; weather 
data (with diagrs.), 171-176 

Morococha Mining Co., 157, 171 

Morro de Arica, 132 

Moss, large ground. See Yareta 

Moss-draped trees (ill.), opp. p. 24 

Mountain-side trail (ill.), opp. p. 78 

Mountains, tropical, as climate registers, 
206 

Mulanquiato, 10, 18, 19 
Mule trail (ill.), opp. p. 18 
Mules, 23, 24, 94, opp. p. 91 (ill.) 

N4v6, 286-305 

Nino, El, 137-138 

Nivation, 285-294; "pocked" surface 

(ill.), opp. p. 286 
Northeastern border, topographic and 

structural section (diagr.), 241 

Occobamba Valley, 79 

Ocean currents of adjacent waters, 121- 
122 (map), 123 



Ollantaytambo, 70, 73, 75, 250, 271; 

terraced valley floor (ill.), opp. p. 

56 
d'Orbigny, 322 
Oruro, 93 

Pabellon, SO, 82, opp. p. 150 

Pacasmayo, Carboniferous land plants, 

245 
Pachitea, 37, 38 
Pacific Ocean basin, 248 
Paleozoic strata (ill.), opp. p. 198 
Palma carmona, 29 
Palmer, H. S., 250 
Paltaybamba, opp. p. 74 
Pampacolca, 109 

Pampaeonas, 69, 211, 213, 215; rounded 
slopes near Vilcabamba (ill.), opp. p. 
72; Carboniferous, 244; fossils, 322; 
snow action, 291 
Pampaeonas Kiver, 316 
Pampas, 114, 19S; climate data, 134-136 
Pampas, river, 189 

Panta, mt., 214; view, with glacier sys- 
tem (ill.), opp. p. 287 
Para rubber, 32 

Pasaje, 51, 57, 59, 60, 236, 238, 240, 241, 
243; Carboniferous, 244; crossing the 
Apurimac (ills.), opp. p. 91 
Paschinger, 274 
Pastures, 141, 187; Alpine (ill.), opp. p. 

58 
Paucartambo, 42, 77 
Paucartambo River. See Yavero River 
Payta, 225 
Penek, A., 205 
Peonage, 25, 27, 28 
Pereira, Senor, 10, 18 
Perene, 155 
Physiographic and geologic development, 

233-273 
Physiographic evidence, value, 193-195 
Physiographic principles, 217 
Physiography, 183-186; Southern Peru, 

summary, 197-198 
Pichu-Pichu, 284 
Piedmont accumulations, 260 
Pilcopata, 36 
Piiii-pini, 36 

Pisco, 130; Carboniferous land plants, 247 
Piura, 119 

Piura River, depth diagram, 119, 120 
Piura Valley, 48 
Place names, key to, 325 



INDEX 



333 



Plantations, 86; see also Haciendas 

Planter, coastal, 6 

Planters, valley, 3, 75, 76 

Plateau Indians, 40-41, 44-45, 100, 106- 
109 

Plateaus, 196-197 

Pleistocene deposits, 267-273 

Pomareni, 19 

Pongo de Mainique, 8, 9, 11, 15-20, 40, 71, 
179, 239, 241, 242, 273; canoe in rapid 
above (ill.)> opp. p. 11; Carboniferous, 
244; dugout in rapids below (ill.), opp. 
p. 2; fossils, 322; temperature curve 
(diagr.), 178; upper entrance (ill.), 
opp. p. 10; vegetation, clearing, and 
rubber station (ill.), opp. p. 2 

Poop5, 195 

Potato field (ill.), opp. p. 67 

Potatoes, 57, 59, 62 

PotosI, 249 

Precipitation. See Rain 

Profiles, composition of slopes and pro- 
files (diagr.), 191 

Pueamoco, 78 

Pucapacures, 42 

Puerto Mainique, 29, 30 

Punas, 6, 197 

Puquiura, 67, 87, 211, 216, 236, 238, 239, 
243, 277; Carboniferous, 244; composi- 
tion of slopes (ill.), opp. p. 198 

Puqura, 250 

Quebradas, 145, 155 
Quechuas, 44, 45, 77, 83 
Quenigo, 285 

Quilca, 105, 117, 226, 266 
Quillabamba, opp. p. 74 
Quillagua, 260 

Railroads, 74, 75, 76, 93, 101-102, 149; 
Bolivia, 93; Cuzco to Santa Ana, 69-70 

Eaimondi, 77, 78, 109, 110, 135, 155, 170, 
316 

Rain, 115, 119, 120, 122, 124-125; coast 
region seasonal variation, 131-137; 
eastern border of Andes, belts (diagrs.), 
148; effect of heavy, 138-140; effect of 
sea-breeze, 131-132; heaviest, 147-148; 
Morocoeha (with diagrs.), 173-176; 
periodic variations, 137; Santa Lucia 
(with diagrs.), 164-166; unequal dis- 
tribution in western Peru, 145-147 

Regional diagrams, 50; index map, 23; 
note on, 51 



Regions of Peru, 1, 7 

Reiss, 205, 208 

Revolutions, geographic basis, 88-109 

Rhone glacier, 205 

Rice, 76 

Robledo, L. M., 9, 30, opp. p. 78 

Rock belts, outline sketch along 73d 
meridian, 235 

Rocks, Maritime Cordillera, pampas and 
Coast Range structural relations 
(sketch section), 254; Maritime Cor- 
dillera, western border (geologic sec- 
tion ) , 257 ; Moquegua, structural rela- 
tions (diagr.), 255; Urubamba Valley, 
succession (diagr.), 249 

Rosalina, 8, 9, 10, 11, 37, 42, 71, 73, 80, 
82, 153, 237 

Rubber, 18; price, 32, 33 

Rubber forests, 22-35 

Rubber gatherers, Italian, 18, 81 

Rubber plant (ill.), opp. p. 75 

Rubber trees, 152 

Rueda, Jos6, 78 

Rug weaver (ill.), opp. p. 68 

Rumbold, W. R., 321 

Russell, I. C, 205 

Ruwenzori, 206, 274 

Sacramento, Pampa del, 37 

Sahuayaco, 77, 78, 80, 83, 179; forests 

(ills.), opp. p. 90; temperature curve 

(diagr.), 178 
Salamanca, 54, 56, 105, 106, 180, 181; 

forest, 285; temperature curve (diagr.), 

180; terraced hill slopes (ill.), opp. p. 

58; view (ill.), opp. p. 107 
Salaverry, 119 

Salcantay, 64, 72, opp. p. 3 (ill.) 
San Geronimo, 276 
Sand. See Dunes 
"Sandy matico " (ill.), opp. p. 90 
San Gabriel, Hacienda, 316 
Santa Ana, 69, 72, 78, 79, 80, 82, 93, 

153, 179, 237; clouds (ill.), opp. 

p. 180; temperature curve (diagr.), 

178 
Santa Ana Valley, 10, 82 
Santa Lucia, temperature ranges (diagrs.), 

insert opp. p. 162; unusual weather 

conditions, 169-170; weather data (with 

diagrs.), 161-171 
Santo Anato, 40, 42, 82, 179; temperature 

cun'e (diagr.), 178 
Schists and Silurian slates, 236-241 



334 



INDEX 



Schrund. See Bergsehrimds 

Schrundline, 300-305 

Schuchert, Chas., 321 

Sea and land. See Land and sea 

Sea-breeze, 129-132 

Shepherd, highland, 4 

Shepherds, country of, 46-67 

Shirineiri, 36, 38 

Sierra Nevada, 305 

Sierra Nevada de Santa Marta, 205 

Sievers, W., 143, 176, 205, 263 

Sihuas, Pampa de, 114, 198 

Sillilica, Cordillera, 190, 260 

Silliliea Pass, 275 

Silurian fossils, 321 

Silurian slates, 236-241 

Sintulini rapids, 19 

Sirialo, 8, 15 

Slave raiders, 14 

Slavery, 24, 25 

Slopes, composition at Puquiura (ill.), 
opp. p. 198; composition of slopes and 
profiles (diagr.), 191; smooth grassy 
(ill.), opp. p. 79; see also Mature 
slopes 

Smallpox, 14, 38 

Snow, 212; drifting, 278; fields on summit 
of Cordillera Vilcapampa (ill.), opp. p. 
268 

Snow erosion. See Nivation 

Snow motion, curve of (diagr.), 293; law 
of variation, 291 

Snowline, 52, 53, 66, 122, 148, 203, 205- 
206, 274-285; canting (with diagr.), 
279; determination, 282; difference in 
degree of canting (diagr.), 281; glacial 
period, 282; view of canted, Cordillera 
Vilcapampa (ill.), opp. p. 280 

Snowstorm, 170 

Soiroccocha, 64, 72, 214; view (ill.), opp. 
p. 154 

Solimana, 4, 202, 317; glaciation, 307 

Soray, 64 

Sotospampa, 243 

South Pacific Ocean, 125 

Spanish Conquest, 62, 63, 77 

Spruce (botanist), 153 

Steinmann, 249, 276 

Streams, Coast Range, 145-147; physiog- 
raphy, 192; see also Water 

Structure. See Eoeks 

Stttbel, 209 

Sucre, 93 

Sugar, 73, 74, 75, 76, 82-83, 92 



Sullana, 119 

Survey methods employed in topographic 
sheets, 315 

Tablazo de lea, 198 

Tarai. See Urubamba Valley 

Tarapacfl, Desert of, 260 

Tarapoto, 153 

Taurisma, 317; gwlogic sketch map and 
cross-section, 248 

Taylor, Capt. A., 126, 128 

Temperature, Abancay curve (diagr.), 
opp. p. 180; Callao (with diagr.), 126- 
129; Cochabamba, 176-178; Cocha- 
bamba (diagrs. of ranges), insert opp. 
p. 178; curves at various points along 
73d meridian, 178-181; La Joya curves 
(diagr.), 134; Mollendo curves (diagr.), 
134; Morococha, 171-173; Morococha 
(diagrs. of ranges), insert opp. p. 172; 
progressive lowering of saturation, in a 
desert (diagr.), 127; Santa Lucia, 161- 
164; Santa Lucia (diagrs. of ranges), 
insert opp. p. 162 

Tempests, 169-170 

Terraces, coastal, 225-232; physical his- 
tory and physiographic development 
(with diagrs.), 228-230; profile at Mol- 
lendo (diagr.), 227 

Terraces, hill slopes (ill.), opp. p. 58 

Terraces, marine (ill.), opp. p. 226 

Terraces, valle}' (ills.), opp. p. 56, opp. 
p. 57, opp. p. 66; Huaynacotas (ill.), 
opp. p. 199 

Terral, 130 

Tertiary deposits, 249, 251-267; coastal, 
253 

Ticumpinea, 36, 38, 251 

Tierra blanca, 254, 266 

Timber line, 09, 71, 79, 148 

Timpia, 36, 38, 252; canoe at mouth 
(ill.), opp. p. 19 

Titicaca, 161, 176, 195, 321 

Titicaca basin, 107 

Titicaca-Poopo basin, 251 

Toeate. See Abra Tocate 

Tola bush (ill.), opp. p. G 

Tono, 36 

Topographic and climatic cross-section 
(diagr.), opp. p. 144 

Topographic and structural section of 
northeastern border of Andes (diagr.), 
241 

Topographic map of the Andes between 



INDEX 



335 



Abaneay and the Pacific Coast at Ca- 
manS, insert opp. p. 312 

Topographic profiles across typical val- 
leys (diagrs.), 189 

Topographic regions, 121-122; map, 123 

Topographic sheets, survey method em- 
ployed, 315; list of, with page refer- 
ences, xi 

Topographical outfit, 315 

Torontoy, 10, 70, 71, 72, 82, 158, 220 

Torontoy Canyon, 272, opp. p. 3 (ill.) ; 
cliflf (ill.), opp. p. 10 

Trail (mountain-side) (ill.), opp. p. 78 

Transportation, 73-74, 93, 152; rains and, 
142 

Trees, 150; see also Forests 

Tucapelle (ship), 117 

Tucker, H. L., ix 

Tumbez, 119 

Tunari peaks, 276 

Ucayali, 42, 44 

Uplift, recent,, 190 

Upper Carboniferous fossils, 322 

Urubamba, 1, 41, 42, 62, 187; village, 70, 
73 

Urubamba River, 72; fossils, 322; physi- 
ographic observations, 252-253; rapids 
and canyons, 8-21; shelter hut (ill.), 
opp. p. 11 

Urubamba Valley, 72, 153, 238; alluvial 
fans, 270; alluvial fill, 272-273; below 
Paltaybamba (ill.), opp. p. 74; canyon 
walls (ill.), opp. p. 218; dissected al- 
luvia] fans (sketch), 271; floor from 
Tarai (ill.), opp. p. 70; from ice to 
sugar cane (ill.), opp. p. 3; geologic 
sketch map of the lower, 237; line of 
unconformity of geologic structure 
(ill.), opp. p. 250; rocks, 250; rooks, 
succession ( diagr. ) , 249 ; sketch map, 9 ; 
slopes and alluvial deposits between 01- 
lantaytambo and Torontoy (ill.), opp. 
p. 269; temperature curves (diagrs.), 
178-179; terraced valley slopes and 
floor (ill.), opp. p. 66; vegetation, dis- 
tribution (ill.), opp. p. 79; view below 
Santa Ana (ill.), opp. p. 155; wheat 
and bread, 71 

Valdivia, Senor, 161 
Vallenar, 49 

Valley climates in canyoned region 
(diagr.), 59 



Valley planters. See Planters 

Valley profiles, abnormal, 305-313 

Valleys, eastern; see Border valleys of the 
Eastern Andes; see also Dry valleys. 
Inter- Andean valleys; topographic pro- 
files across, typical in Southern Peru 
(diagrs.), 189 

Vegetation, 141; belts (map), 123; dis- 
tribution in Urubamba Valley (ill.), 
opp. p. 79 ; shrubbery, mixed with grass 
(ill.), opp. p. 154; Tocate pass (ill.), 
opp. p. 19; see also Forests 

Vicuna, 54 

Vileabamba, 66; rounded slopes (ill.), opp. 
p. 72 

Vileabamba pueblo, 211, 277, 296 

Vileabamba Valley, 189 

Vilcanota knot, 276 

Vilcanota Valley, alluvial fill, 272 

Vilcapampa, Cordillera, 15, 16, 22, 51, 53, 
64, 66 67, 197, 204-224, 233; batholith 
and topographic efl'ects, 215-224; canted 
snowline (ill.), opp. p. 280; climatic 
barrier, 73; composite geologic section 
(diagr.), 215; glacial features, 204-214; 
glaciers, 304; highest pass, crossing 
(ill.), opp. p. 7; regional diagram, 65; 
regional diagram of the eastern aspect, 
68; schrundline, 302; snow movement, 
287-289; snow fields on summit (ill.), 
opp. p. 268; snow peaks (ill.), opp. p. 
72; snowline, 277, 279; southwestern as- 
pect (ill.), opp. p. 205; summit view 
(ill.), opp. p. 205 

Vilcapampa Province, 77 

Vilcapampa Valley, bowldery fill, 269 

Vilque, 176 

Violle, 309 

Virazoii, 130 

Vitor, Pampa de, 114, 318 

Vitor River, 92, 117, 226, 266, 267 

Volcanic country, 199 

Volcanic flows, geologic sketch, 244 

Volcanoes, glacial erosion, 311; post- 
glacial, 306-307; recessed southern 
slopes (ill.), opp. p. 287; snowline, 281; 
typical form, 310; views (ills.), opp. p. 
204 

Von Boeck, 176 

Vulcanism, 199; see also Volcanoes 

Ward, R. De C, 126, 143 
Water, 59, 60, 116, 139; projected canal 
from Atlantic to Pacific slope of the 



336 



INDEX 



Maritime Cordillera (diagr. ), US; 
streams of coastal desert, intermittent 
and perennial, diagrams of depth, 119 

Water skippers, 17 

Watkins, Mr., 317, 318 

Weather. See Meteorological records 

Western Andes, 199-203 

Whymper, 205 

Wind belts, 122; map, 123 

Wind roses, Callao (diagrs. ), 128; Cara- 
veli (diagrs.), 136; Iquique (diagrs.), 
131; La Joya (diagrs.), 135; Machu 
Piechu (diagrs.), 159; Mollendo 
(diagrs.), 129; Santa Lucia (diagrs.), 
167; summer and winter of 1911-1913 
(diagrs.), 130 

Winds, 114, 115; directions at Machu 
Piechu, 158-159; geologic action, 262- 



267; prevailing, 125; Santa Lucia 
(with diagrs.), 166-168; trade, 122, 124; 
sea-breeze, 129-132 

Wine, 116, 117 

Wolf, 205 

Yanahuara pass, 170 

Yanatili, 41, 42, 44; slopes at junction 
with Urubamba River (ill.), opp. p. 
79 

Tareta (ill.), opp. p. 6 

Yavero, 30, 31, 36, 38, 42, 179; tempera- 
ture cur\'e (diagr.), 178 

Yavero (Paucartambo) River, rubber sta- 
tion (ill.), opp. p. 24 

Yuca, growing (ill.), opp. p. 75 

Yunguyo, 176 

Yuyato, 36, 38 



rAViG 



-1 



n^h 



